message: Make TF unittests use TEST_TMPDIR if it is set.
diff: @@ -104,6 +104,9 @@ def GetTempDir():
  """Return a temporary directory for tests to use."""
  global _googletest_temp_dir
  if not _googletest_temp_dir:
  + if os.environ.get('TEST_TMPDIR'):
  + temp_dir = tempfile.mkdtemp(prefix=os.environ['TEST_TMPDIR'])
  + else:
  first_frame = tf_inspect.stack()[-1][0]
  temp_dir = os.path.join(tempfile.gettempdir(),
  os.path.basename(tf_inspect.getfile(first_frame)))
  