Port adaptive_max_pool2d_backward to structured kernel (#56799)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/56799
Test Plan: Imported from OSS
Reviewed By: ezyang
Differential Revision: D27984078
Pulled By: SplitInfinity
fbshipit-source-id: 6404513f413fc6966687d8f1e9ea2a423a332ec9
