Support non-tensor inputs and outputs for checkpointed functions. (#52422)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/52422
As mentioned in https://github.com/pytorch/pytorch/issues/52415,
`torch.utils.checkpoint` doesn't support checkpointing for functions which have
non-tensor inputs and outputs.
This PR resolves this issue by ensuring the autograd machinery ignores the
non-tensor inputs and outputs and processes the tensors accordingly.
ghstack-source-id: 124406867
Test Plan:
1) unit test
2) waitforbuildbot
Reviewed By: albanD
Differential Revision: D26507228
fbshipit-source-id: 0a5a1591570814176185362e83ad18dabd9c84b0
