Fix stdio-common tests for GCC 12 -Waddress

My glibc bot shows failures building the testsuite with GCC mainline
across all architectures:

tst-vfprintf-width-prec.c: In function 'do_test':
tst-vfprintf-width-prec.c:90:16: error: the comparison will always evaluate as 'false' for the address of 'result' will never be NULL [-Werror=address]
   90 |     if (result == NULL)
      |                ^~
tst-vfprintf-width-prec.c:89:13: note: 'result' declared here
   89 |     wchar_t result[100];
      |             ^~~~~~

This is clearly a correct warning; the comparison against NULL is
clearly a cut-and-paste mistake from an earlier case in the test that
does use calloc.  Thus, remove the unnecessary check for NULL shown up
by the warning.

Similarly, two other tests have bogus comparisons against NULL; remove
those as well:

scanf14a.c:95:13: error: the comparison will always evaluate as 'false' for the address of 'fname' will never be NULL [-Werror=address]
   95 |   if (fname == NULL)
      |             ^~
scanf14a.c:93:8: note: 'fname' declared here
   93 |   char fname[strlen (tmpdir) + sizeof "/tst-scanf14.XXXXXX"];
      |        ^~~~~

scanf16a.c:125:13: error: the comparison will always evaluate as 'false' for the address of 'fname' will never be NULL [-Werror=address]
  125 |   if (fname == NULL)
      |             ^~
scanf16a.c:123:8: note: 'fname' declared here
  123 |   char fname[strlen (tmpdir) + sizeof "/tst-scanf16.XXXXXX"];
      |        ^~~~~

Tested with build-many-glibcs.py (GCC mainline) for aarch64-linux-gnu.

1 files changed, 0 insertions, 2 deletions

diff --git a/stdio-common/scanf16a.c b/stdio-common/scanf16a.c
index 400d85a54e..74d0295c97 100644
--- a/stdio-common/scanf16a.c
+++ b/stdio-common/scanf16a.c
@@ -122,8 +122,6 @@ main (void)
 
   char fname[strlen (tmpdir) + sizeof "/tst-scanf16.XXXXXX"];
   sprintf (fname, "%s/tst-scanf16.XXXXXX", tmpdir);
-  if (fname == NULL)
-    FAIL ();
 
   /* Create a temporary file.   */
   int fd = mkstemp (fname);