Fix auto exponent issue for torch.pow (#47024)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47024
Fixes https://github.com/pytorch/pytorch/issues/46936
Stack from [ghstack](https://github.com/ezyang/ghstack):
* **#47024 Fix auto exponent issue for torch.pow**
Test Plan: Imported from OSS
Reviewed By: malfet
Differential Revision: D24698027
Pulled By: anjali411
fbshipit-source-id: f23fdb65c925166243593036e08214c4f041a63d
