add AdaptiveAvgPooling2D (#61239)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/61239
Test Plan: Imported from OSS
Reviewed By: iramazanli
Differential Revision: D29626359
Pulled By: migeed-z
fbshipit-source-id: b7cd4ce4176e2d6e7a853974443affd23a49d3d9
