pytorch

e926f75b - BatchNorm autodiff re-enabled (#57321)

BatchNorm autodiff re-enabled (#57321) Summary: Turns on BN in autodiff: 1. outputs an empty tensor for running stats to by pass autodiff issue on None; 2. fixing BN inference backward in cudnn & miopen, where backward falls back to native batchnorm kernel instead; Pull Request resolved: https://github.com/pytorch/pytorch/pull/57321 Reviewed By: albanD, ngimel Differential Revision: D30250419 Pulled By: jansel fbshipit-source-id: a62553789c20fb50a820003a056f40d9d642dfaa