Issue #12400: fix test_faulthandler if regrtest captures sys.stderr
Issue #12400: fix test_faulthandler if regrtest captures sys.stderr

faulthandler.enable() requires that sys.stderr has a fileno() method.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator