Bring back the optimization of integer.pow({2.0, 3.0}) on CPU (#26938)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/26938
They were accidentally removed in #26020
Test Plan: Imported from OSS
Differential Revision: D17632120
Pulled By: pbelevich
fbshipit-source-id: d62f2b5635fb4976fd4eda2f2015fdf67138a0c0
