message: Make tower-local variables non-trainable even with the default
  DistributionStrategy.
diff: @@ -1127,8 +1127,7 @@ class _DefaultDistributionStrategy(DistributionStrategy):
  def creator(next_creator, *args, **kwargs):
  _require_distribution_strategy_scope(self)
  - if kwargs.pop("tower_local_reduce_method", None) is not None:
  - kwargs["trainable"] = False
  + kwargs.pop("tower_local_reduce_method", None)
  return next_creator(*args, **kwargs)
  return _CurrentDistributionContext(
  @@ -1138,7 +1137,7 @@ class _DefaultDistributionStrategy(DistributionStrategy):
  """Does not set to resource variables."""
  def create_tower_local_variable(next_creator, *args, **kwargs):
  _require_distribution_strategy_scope(self)
  - kwargs["tower_local_reduce_method"] = reduce_method
  + kwargs["trainable"] = False
  return next_creator(*args, **kwargs)
  _require_distribution_strategy_scope(self)
  