Use os.path.isfile for checking if path.is_file, suppresses exception…

Use os.path.isfile for checking if path.is_file, suppresses exception… · pypa/distutils@6852b20

Original file line number	Diff line number	Diff line change
`@@ -258,7 +258,6 @@ def test_find_config_files_disable(self, temp_home):`
`258`	`258`	`# make sure --no-user-cfg disables the user cfg file`
`259`	`259`	`assert len(all_files) - 1 == len(files)`
`260`	`260`
`261`		`-@pytest.mark.xfail(reason="pypa/distutils#181", strict=True)`
`262`	`261`	`@pytest.mark.skipif(`
`263`	`262`	`'platform.system() == "Windows"',`
`264`	`263`	`reason='Windows does not honor chmod 000',`