message: Use the executing_eagerly local variable instead of recomputing it
  (Not exactly a ground-breaking change, but it was annoying me.)
diff: @@ -740,7 +740,7 @@ class ConcreteFunction(object):
  possible_gradient_type = _PossibleTapeGradientTypes(
  pywrap_tensorflow.TFE_Py_TapeSetPossibleGradientTypes(args))
  if possible_gradient_type == _PossibleTapeGradientTypes.FIRST_ORDER:
  - if context.executing_eagerly():
  + if executing_eagerly:
  # There is a single non-persistent tape active, so the user can only
  # request first-order gradients from a tape. We can spend less time
  # graph building since we know this.
  @@ -773,7 +773,7 @@ class ConcreteFunction(object):
  # tape is recording.
  # Only need to override the gradient in graph mode and when we have outputs.
  - if context.executing_eagerly() or not self.outputs:
  + if executing_eagerly or not self.outputs:
  outputs = self._inference_function.call(
  ctx, args, cancellation_manager=cancellation_manager)
  else:
  