Change w3c-test-expectations file name

third_party/WebKit/Tools/Scripts/update-w3c-test-expectations

 #!/usr/bin/env python
 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import sys
 
 from webkitpy.common import host
 from webkitpy.common.checkout.scm.git import Git
 from webkitpy.w3c.update_w3c_test_expectations import main
 
 if __name__ == "__main__":
     host = host.Host()
     host.initialize_scm()
     port = host.port_factory.get()
     return_code = main(host, port)
 
 sys.exit(return_code)