[FX] Try to make it more clear that _update_args_kwargs should not be called (#49745)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/49745
Test Plan: Imported from OSS
Reviewed By: zdevito
Differential Revision: D25682177
Pulled By: jamesr66a
fbshipit-source-id: 4910577541c4d41e1be50a7aa061873f061825b6
