Adds a filter to run-test-suites.pl to exclude data files

The run-test-suites.pl script was executing all files of the form 'test_suite*'
which were either executable or ended with a .exe extension.

On some filesystems, such as through network shares or VMs, which are
abstracting one set of file permissions to Unix permissions, may set the
executable permissions on all files, whether they're executable or not.

That was leading to the run-test-suites.pl script to attempt to execute the .c
intermediate files because they followed the form 'test_suite_*.c'. This change
now excludes them, just in case they accidentally have execute permissions.
diff --git a/tests/scripts/run-test-suites.pl b/tests/scripts/run-test-suites.pl
index 6279358..9d362f3 100755
--- a/tests/scripts/run-test-suites.pl
+++ b/tests/scripts/run-test-suites.pl
@@ -35,8 +35,9 @@
 
 # All test suites = executable files, excluding source files, debug
 # and profiling information, etc. We can't just grep {! /\./} because
-#some of our test cases' base names contain a dot.
+# some of our test cases' base names contain a dot.
 my @suites = grep { -x $_ || /\.exe$/ } glob 'test_suite_*';
+@suites = grep { !/\.c$/ && !/\.data$/ } @suites;
 die "$0: no test suite found\n" unless @suites;
 
 # in case test suites are linked dynamically