Disables all WindowManagerAppTest as they are flakey

testing/scripts/mojo_apptests.py

 #!/usr/bin/env python
 # Copyright 2015 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 json
 import os
 import sys
 
 
@@ skipping 16 matching lines @@
   json.dump({
       'valid': bool(rc <= common.MAX_FAILURES_EXIT_STATUS and
                    ((rc == 0) or failures)),
       'failures': failures.keys(),
   }, args.output)
 
   return rc
 
 
 def main_compile_targets(args):
-  json.dump(['mandoline:tests'], args.output)
+  json.dump(['mandoline:tests', 'mash/wm:tests'], args.output)
 
 
 if __name__ == '__main__':
   funcs = {
     'run': main_run,
     'compile_targets': main_compile_targets,
   }
   sys.exit(common.run_script(sys.argv[1:], funcs))