Improve tests for error reporting in Filesystem TS
* testsuite/experimental/filesystem/iterators/
recursive_directory_iterator.cc: Ensure that error_code arguments are
cleared when required.
* testsuite/experimental/filesystem/operations/create_directory.cc:
Remove redundant check.
* testsuite/experimental/filesystem/operations/temp_directory_path.cc:
Ensure that error_code argument is cleared when required.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@253897 138bc75d-0d04-0410-961f-82ee72b054a4