[vulkan][op] avg_pool2d (#42675)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/42675
Test Plan: Imported from OSS
Reviewed By: AshkanAliabadi
Differential Revision: D22978765
Pulled By: IvanKobzarev
fbshipit-source-id: 64938d8965aeeb408dd5c40d688eca13fb7ebb8a
