resubmit: "resubmit: [mta] APEX style Fused Adam (#81705) (#85507)" (#85739)
Embarrassingly move the pow implementations around [ATen/native/cuda/PowKernel.cu#L21-L66](https://github.com/pytorch/pytorch/blob/849b08f14b2a741d0b90bb7bfce0ebb3d07d1981/aten/src/ATen/native/cuda/PowKernel.cu#L21-L66) to a new header file and let FusedAdam use them to tame MSVC, hopefully.
cc @ngimel @ptrblck
Pull Request resolved: https://github.com/pytorch/pytorch/pull/85739
Approved by: https://github.com/ngimel
