Revert "Add meta support for _adaptive_avg_pool2d_backward (#86359)"
This reverts commit a56a8c0fc0251bb4cd24b366a290db2e4beea747.
Reverted https://github.com/pytorch/pytorch/pull/86359 on behalf of https://github.com/clee2000 due to causing unexpected success for functorch on master but PR is green (landrace?) https://github.com/pytorch/pytorch/actions/runs/3227306657/jobs/5282180524 https://hud.pytorch.org/pytorch/pytorch/commit/a56a8c0fc0251bb4cd24b366a290db2e4beea747
