Workaround python time.strptime flake in Android tests

build/android/test_runner.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.
 
 """Runs all types of tests from one unified interface."""
 
 import argparse
 import collections
 import contextlib
 import itertools
 import logging
 import os
 import shutil
 import signal
 import sys
 import threading
 import traceback
 import unittest
 
+# Import _strptime before threaded code. datetime.datetime.strptime is
+# threadsafe except for the initial import of the _strptime module.
+# See http://crbug.com/724524 and https://bugs.python.org/issue7980.
+import _strptime  # pylint: disable=unused-import
+
 from pylib.constants import host_paths
 
 if host_paths.DEVIL_PATH not in sys.path:
   sys.path.append(host_paths.DEVIL_PATH)
 
 from devil import base_error
 from devil.utils import reraiser_thread
 from devil.utils import run_tests_helper
 
 from pylib import constants
@@ skipping 893 matching lines @@
     if e.is_infra_error:
       return constants.INFRA_EXIT_CODE
     return constants.ERROR_EXIT_CODE
   except: # pylint: disable=W0702
     logging.exception('Unrecognized error occurred.')
     return constants.ERROR_EXIT_CODE
 
 
 if __name__ == '__main__':
   sys.exit(main())