Revert "reuse open(2) from rb_file_load_ok on POSIX-like system"

This reverts commit 35136e1e9c232ad7a03407b992b2e86b6df43f63.

test-spec has been failing since this revision.

.github/workflows/compilers.yml:82
https://github.com/ruby/ruby/actions/runs/4276884159/jobs/7445299562

```
env:
  # Minimal flags to pass the check.
  default_cc: 'gcc-11 -fcf-protection -Wa,--generate-missing-build-notes=yes'
  optflags: '-O2'
  LDFLAGS: '-Wl,-z,now'
  # FIXME: Drop skipping options
  # https://bugs.ruby-lang.org/issues/18061
  # https://sourceware.org/annobin/annobin.html/Test-pie.html
  TEST_ANNOCHECK_OPTS: "--skip-pie --skip-gaps"
```

Failure:

```
  1)
  An exception occurred during: Kernel#require (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:317
  Kernel#require (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded ERROR
  LeakError: Leaked file descriptor: 8 : #<File:/__w/ruby/ruby/src/spec/ruby/fixtures/code/load_fixture.ext.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:5:in `<top (required)>'

  2)
  An exception occurred during: Kernel#require ($LOADED_FEATURES) stores an absolute path
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:330
  Kernel#require ($LOADED_FEATURES) stores an absolute path ERROR
  LeakError: Closed file descriptor: 8
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:5:in `<top (required)>'

  3)
  An exception occurred during: Kernel#require ($LOADED_FEATURES) does not load a non-canonical path for a file already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:535
  Kernel#require ($LOADED_FEATURES) does not load a non-canonical path for a file already loaded ERROR
  LeakError: Leaked file descriptor: 8 : #<File:/__w/ruby/ruby/src/spec/ruby/fixtures/code/load_fixture.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:5:in `<top (required)>'

  4)
  An exception occurred during: Kernel#require ($LOADED_FEATURES) does not load a ../ relative path for a file already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:551
  Kernel#require ($LOADED_FEATURES) does not load a ../ relative path for a file already loaded ERROR
  LeakError: Leaked file descriptor: 9 : #<File:../code/load_fixture.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:5:in `<top (required)>'

  5)
  An exception occurred during: Kernel#require ($LOADED_FEATURES) complex, enumerator, rational, thread, ruby2_keywords are already required
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:563
  Kernel#require ($LOADED_FEATURES) complex, enumerator, rational, thread, ruby2_keywords are already required ERROR
  LeakError: Closed file descriptor: 8
  Closed file descriptor: 9
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:5:in `<top (required)>'

  6)
  An exception occurred during: Kernel.require (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:317
  Kernel.require (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded ERROR
  LeakError: Leaked file descriptor: 8 : #<File:/__w/ruby/ruby/src/spec/ruby/fixtures/code/load_fixture.ext.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:23:in `<top (required)>'

  7)
  An exception occurred during: Kernel.require ($LOADED_FEATURES) stores an absolute path
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:330
  Kernel.require ($LOADED_FEATURES) stores an absolute path ERROR
  LeakError: Closed file descriptor: 8
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:23:in `<top (required)>'

  8)
  An exception occurred during: Kernel.require ($LOADED_FEATURES) does not load a non-canonical path for a file already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:535
  Kernel.require ($LOADED_FEATURES) does not load a non-canonical path for a file already loaded ERROR
  LeakError: Leaked file descriptor: 8 : #<File:/__w/ruby/ruby/src/spec/ruby/fixtures/code/load_fixture.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:23:in `<top (required)>'

  9)
  An exception occurred during: Kernel.require ($LOADED_FEATURES) does not load a ../ relative path for a file already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:551
  Kernel.require ($LOADED_FEATURES) does not load a ../ relative path for a file already loaded ERROR
  LeakError: Leaked file descriptor: 9 : #<File:../code/load_fixture.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:23:in `<top (required)>'

  10)
  An exception occurred during: Kernel.require ($LOADED_FEATURES) complex, enumerator, rational, thread, ruby2_keywords are already required
  /__w/ruby/ruby/src/spec/ruby/core/kernel/shared/require.rb:563
  Kernel.require ($LOADED_FEATURES) complex, enumerator, rational, thread, ruby2_keywords are already required ERROR
  LeakError: Closed file descriptor: 8
  Closed file descriptor: 9
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_spec.rb:23:in `<top (required)>'

  11)
  An exception occurred during: Kernel#require_relative with a relative path (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:197
  Kernel#require_relative with a relative path (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded ERROR
  LeakError: Leaked file descriptor: 8 : #<File:/__w/ruby/ruby/src/spec/ruby/fixtures/code/load_fixture.ext.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:4:in `<top (required)>'

  12)
  An exception occurred during: Kernel#require_relative with a relative path ($LOADED_FEATURES) stores an absolute path
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:205
  Kernel#require_relative with a relative path ($LOADED_FEATURES) stores an absolute path ERROR
  LeakError: Closed file descriptor: 8
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:4:in `<top (required)>'

  13)
  An exception occurred during: Kernel#require_relative with an absolute path (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:399
  Kernel#require_relative with an absolute path (file extensions) does not load a C-extension file if a complex-extensioned .rb file is already loaded ERROR
  LeakError: Leaked file descriptor: 8 : #<File:/__w/ruby/ruby/src/spec/ruby/fixtures/code/load_fixture.ext.rb>
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:277:in `<top (required)>'

  14)
  An exception occurred during: Kernel#require_relative with an absolute path ($LOAD_FEATURES) stores an absolute path
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:407
  Kernel#require_relative with an absolute path ($LOAD_FEATURES) stores an absolute path ERROR
  LeakError: Closed file descriptor: 8
  /__w/ruby/ruby/src/spec/ruby/core/kernel/require_relative_spec.rb:277:in `<top (required)>'
```

2 files changed, 1 insertions, 16 deletions

diff --git a/internal/file.h b/internal/file.h
index 2768418ac5..9c192ff4d1 100644
--- a/internal/file.h
+++ b/internal/file.h
@@ -11,14 +11,6 @@
 #include "ruby/ruby.h"          /* for VALUE */
 #include "ruby/encoding.h"      /* for rb_encodinng */
 
-struct ruby_file_load_state {
-    /* TODO: consider stuffing `VALUE fname' here */
-    VALUE filev;
-    unsigned int is_fifo:1;
-    unsigned int is_nonblock:1;
-    /* TODO: DOSISH / __CYGWIN__ maintainer may add xflag here */
-};
-
 /* file.c */
 extern const char ruby_null_device[];
 VALUE rb_home_dir_of(VALUE user, VALUE result);
@@ -26,16 +18,12 @@ VALUE rb_default_home_dir(VALUE result);
 VALUE rb_realpath_internal(VALUE basedir, VALUE path, int strict);
 VALUE rb_check_realpath(VALUE basedir, VALUE path, rb_encoding *origenc);
 void rb_file_const(const char*, VALUE);
-int rb_file_load_ok(const char *, struct ruby_file_load_state *);
+int rb_file_load_ok(const char *);
 VALUE rb_file_expand_path_fast(VALUE, VALUE);
 VALUE rb_file_expand_path_internal(VALUE, VALUE, int, int, VALUE);
 VALUE rb_get_path_check_to_string(VALUE);
 VALUE rb_get_path_check_convert(VALUE);
 int ruby_is_fd_loadable(int fd);
-int ruby_disable_nonblock(int fd);
-int ruby_find_file_ext(VALUE *filep, const char *const *ext,
-                        struct ruby_file_load_state *);
-VALUE ruby_find_file(VALUE path, struct ruby_file_load_state *);
 
 RUBY_SYMBOL_EXPORT_BEGIN
 /* file.c (export) */
diff --git a/internal/parse.h b/internal/parse.h
index 7cadd0cd5b..f242c384ad 100644
--- a/internal/parse.h
+++ b/internal/parse.h
@@ -10,13 +10,10 @@
  */
 #include "ruby/ruby.h"          /* for VALUE */
 struct rb_iseq_struct;          /* in vm_core.h */
-struct ruby_file_load_state;    /* internal/file.h */
 
 /* parse.y */
 VALUE rb_parser_set_yydebug(VALUE, VALUE);
 void *rb_parser_load_file(VALUE parser, VALUE name);
-void *rb_parser_load_state(VALUE parser, VALUE name,
-                        struct ruby_file_load_state *);
 void rb_parser_keep_script_lines(VALUE vparser);
 void rb_parser_error_tolerant(VALUE vparser);
 void rb_parser_keep_tokens(VALUE vparser);