Move to using MemoryFormat::ChannelsLast for avgpool2d. (#36812)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/36812
ghstack-source-id: 103218413
Test Plan: Quantized op tests.
Reviewed By: z-a-f
Differential Revision: D21093839
fbshipit-source-id: 9b68916e56684efb80dd131eece655a7f3779362
