message: Support gradient_multipliers as tensor for optimize_loss
  This fix tries to address the issue raised in 22295 where
  gradient_multipliers for tf.contrib.layers.optimize_loss()
  does not support tensor as input. This fix update the
  optimize_loss to allow gradient_multipliers passed as dict
  of tensors.
  This fix fixes 22295.
diff: @@ -433,8 +433,7 @@ def _multiply_gradients(grads_and_vars, gradient_multipliers):
  if (grad is not None and
  (var in gradient_multipliers or var.name in gradient_multipliers)):
  key = var if var in gradient_multipliers else var.name
  - multiplier = constant_op.constant(
  - gradient_multipliers[key], dtype=dtypes.float32)
  + multiplier = gradient_multipliers[key]
  if isinstance(grad, ops.IndexedSlices):
  grad_values = grad.values * multiplier
  grad = ops.IndexedSlices(grad_values, grad.indices, grad.dense_shape)
  