message: Add shape debug output to Reshape errors.
  It's often difficult to know which tensor failed to reshape, and knowing the input and output shapes can help track it down.
diff: @@ -89,7 +89,8 @@ void Reshape(OpKernelContext *context, const Tensor &input_indices_in,
  errors::InvalidArgument(
  "Input to reshape is a SparseTensor with ", dense_size,
  " dense values, but the requested shape requires a multiple of ",
  - product));
  + product, ". input_shape=", input_shape.DebugString(),
  + " output_shape=", output_shape.DebugString()));
  output_shape.set_dim(unknown_index, missing);
  }
  @@ -97,7 +98,9 @@ void Reshape(OpKernelContext *context, const Tensor &input_indices_in,
  context, output_shape.num_elements() == dense_size,
  errors::InvalidArgument("Input to reshape is a tensor with ", dense_size,
  " dense values, but the requested shape has ",
  - output_shape.num_elements()));
  + output_shape.num_elements(),
  + ". input_shape=", input_shape.DebugString(),
  + " output_shape=", output_shape.DebugString()));
  // Optimize for reshaping to the same shape.
  if (input_shape == output_shape) {
  