Set the Swarm Test encoding to UTF-8

tests/swarming_test.py

 #!/usr/bin/env python
 # Copyright 2013 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 hashlib
 import json
 import logging
 import os
 import StringIO
@@ skipping 412 matching lines @@
       {
         u'config_name': os_value,
         u'dimensions': {
           u'os': os_value,
         },
         u'min_instances': shards,
         u'priority': 101,
       },
     ],
     u'data': [],
+    u'encoding': 'UTF-8',
     u'env_vars': {},
     u'restart_on_failure': True,
     u'test_case_name': TEST_NAME,
     u'tests': chromium_tasks(isolate_server),
     u'working_dir': unicode(working_dir),
   }
   if shards > 1:
     expected[u'env_vars'][u'GTEST_SHARD_INDEX'] = u'%(instance_index)s'
     expected[u'env_vars'][u'GTEST_TOTAL_SHARDS'] = u'%(num_instances)s'
   if profile:
@@ skipping 176 matching lines @@
           'Usage: swarming.py trigger [options]\n\n'
           'swarming.py: error: At least one --task is required.\n')
 
 
 if __name__ == '__main__':
   logging.basicConfig(
       level=logging.DEBUG if '-v' in sys.argv else logging.ERROR)
   if '-v' in sys.argv:
     unittest.TestCase.maxDiff = None
   unittest.main()