Revise update-w3c-deps to check in tests directly

Tools/Scripts/webkitpy/common/system/systemhost.py

 # Copyright (c) 2011 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 35 matching lines @@
         self.stderr = sys.stderr
 
     def copy_current_environment(self):
         return environment.Environment(os.environ.copy())
 
     def print_(self, *args, **kwargs):
         sep = kwargs.get('sep', ' ')
         end = kwargs.get('end', '\n')
         stream = kwargs.get('stream', self.stdout)
         stream.write(sep.join([str(arg) for arg in args]) + end)
+
+    def exit(self, returncode):
+        sys.exit(returncode)