Fix max_pool2d with ceil_mode bug (#46558)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/46558
This PR fixes a bug with how pooling output shape was computed.
## BC Breaking Notes
Previously, a bug in the pooling code allowed a sliding window to be entirely off bounds. Now, sliding windows must start inside the input or left padding (not right padding, see https://github.com/pytorch/pytorch/issues/46929) and may only go off-bounds if ceil_mode=True.
fixes #45357
TODO
- [x] Ensure existing tests are checking for the correct output size
Test Plan: Imported from OSS
Reviewed By: albanD
Differential Revision: D24633372
Pulled By: heitorschueroff
fbshipit-source-id: 55925243a53df5d6131a1983076f11cab7516d6b
