test infra - Under -DNO_TAINT_SUPPORT skip tests that use -T or -t

This patch uses a collection of heuristics to skip test files which
would die on a perl compiled with -DNO_TAINT_SUPPORT but without
-DSILENT_NO_TAINT_SUPPORT.

-DNO_TAINT_SUPPORT disables taint support in a "safe" way, such that if
you try to use taint mode with the -t or -T options an exception will be
thrown informing you that the perl you are using does not support taint.
(The related setting -DSILENT_NO_TAINT_SUPPORT disables taint support
but causes the -t and -T options to be silently ignored.)

The error from using -t and -T is thrown very early in the process
startup and there is no way to "gracefully" handle it and convert it
into something else, for instance to skip a test file which contains it.

This patch generally fixes our code to skip these tests.

* Make t/TEST and t/harness check shebang lines and use filename checks
  to filter out tests that use -t or -T. Primarily this is the result of
  checking their shebang line, but some cpan/ files are excluded by
  name, either from a very short list of exclusions, or because their
  file name contains the word "taint". Non-cpan test files were fixed
  individually as noted below.

* test.pl - make run_multiple_progs() skip test cases based on the
  switches that are part of the test definition. This function is
  used in a great deal of our internal tests, so it fixes a lot of
  tests in one go.

* XS-APITest/t/call.t, t/run/switchDX.t, lib/B/Deparse.t - Skip a small
  set of tests in each file.

1 files changed, 19 insertions, 10 deletions

diff --git a/lib/B/Deparse.t b/lib/B/Deparse.t
index 8cd3fb4d27..eb6bcc3828 100644
--- a/lib/B/Deparse.t
+++ b/lib/B/Deparse.t
@@ -307,14 +307,19 @@ x(); z()
 .
 EOCODH
 
-is runperl(stderr => 1, switches => [ '-MO=-qq,Deparse', $path, '-T' ],
+SKIP: {
+    skip("Your perl was built without taint support", 1)
+        unless $Config::Config{taint_support};
+
+    is runperl(stderr => 1, switches => [ '-MO=-qq,Deparse', $path, '-T' ],
            prog => "format =\n\@\n\$;\n.\n"),
-   <<'EOCODM', '$; on format line';
-format STDOUT =
-@
-$;
-.
-EOCODM
+        <<~'EOCODM', '$; on format line';
+        format STDOUT =
+        @
+        $;
+        .
+        EOCODM
+}
 
 is runperl(stderr => 1, switches => [ '-MO=-qq,Deparse,-l', $path ],
            prog => "format =\n\@\n\$foo\n.\n"),
@@ -537,10 +542,14 @@ is runperl(stderr => 1, switches => [ '-MO=-qq,Deparse', $path ],
    "sub BEGIN {\n    \$main::{'f'} = \\!0;\n}\n",
    '&PL_sv_yes constant (used to croak)';
 
-is runperl(stderr => 1, switches => [ '-MO=-qq,Deparse', $path, '-T' ],
+SKIP: {
+    skip("Your perl was built without taint support", 1)
+        unless $Config::Config{taint_support};
+    is runperl(stderr => 1, switches => [ '-MO=-qq,Deparse', $path, '-T' ],
            prog => '$x =~ (1?/$a/:0)'),
-  '$x =~ ($_ =~ /$a/);'."\n",
-  '$foo =~ <branch-folded match> under taint mode';
+        '$x =~ ($_ =~ /$a/);'."\n",
+        '$foo =~ <branch-folded match> under taint mode';
+}
 
 unlike runperl(stderr => 1, switches => [ '-MO=-qq,Deparse', $path, '-w' ],
                prog => 'BEGIN { undef &foo }'),