libstdc++: Fix experimental::filesystem::status on Windows [PR88881]

libstdc++: Fix experimental::filesystem::status on Windows [PR88881]

Although the Filesystem TS isn't properly supported on Windows (unlike
the C++17 Filesystem lib), most tests do pass. Two of the failures are
due to PR 88881 which was only fixed for std::filesystem not the TS.
This applies the fix to the TS implementation too.

libstdc++-v3/ChangeLog:

	PR libstdc++/88881
	* src/filesystem/ops.cc (has_trailing_slash): New helper
	function.
	(fs::status): Strip trailing slashes.
	(fs::symlink_status): Likewise.
	* testsuite/experimental/filesystem/operations/temp_directory_path.cc:
	Clean the environment before each test and use TMP instead of
	TMPDIR so the test passes on Windows.