message: Pass 'mode' argument to input_fn if appropriate in TPUEstimator.
diff: @@ -1763,6 +1763,9 @@ class TPUEstimator(estimator_lib.Estimator):
  if 'config' in input_fn_args:
  kwargs['config'] = config
  + if 'mode' in input_fn_args:
  + kwargs['mode'] = mode
  +
  with self._ctx.with_mode(mode) as ctx:
  # Setting the batch size in params first. This helps user to have same
  # input_fn for use_tpu=True/False.
  