add `OpInfo` for `torch.nn.functional.dropout` (#62315)
Summary:
Addresses facebookresearch/functorch#78.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/62315
Reviewed By: mruberry
Differential Revision: D30932765
Pulled By: zou3519
fbshipit-source-id: 481c67b59a966b4d640973d252b3e392d8db728e
