[CheckpointWrapper] Test for kwarg propagation, remove checkpoint_fn_arg support (#102679)
Closes https://github.com/pytorch/pytorch/issues/100576
Differential Revision: [D46342398](https://our.internmc.facebook.com/intern/diff/D46342398/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/102679
Approved by: https://github.com/awgu
