optimize channels last for BatchNorm2d on CPU (#48919)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/48919
move data indexing utils
parallel inference contiguous path
parallel inference channels last path
add dim apply
optimize update stats
add channels last support for backward
Revert "add channels last support for backward"
This reverts commit cc5e29dce44395250f8e2abf9772f0b99f4bcf3a.
Revert "optimize update stats"
This reverts commit 7cc6540701448b9cfd5833e36c745b5015ae7643.
Revert "add dim apply"
This reverts commit b043786d8ef72dee5cf85b5818fcb25028896ecd.
bug fix
add batchnorm nhwc test for cpu, including C=1 and HW=1
Test Plan: Imported from OSS
Reviewed By: glaringlee
Differential Revision: D25399468
Pulled By: VitalyFedyunin
fbshipit-source-id: a4cd7a09cd4e1a8f5cdd79c7c32c696d0db386bd
