Fix auto exponent issue for torch.pow (#49809)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/49809
Fixes https://github.com/pytorch/xla/issues/2688 #46936
Test Plan: Imported from OSS
Reviewed By: nikithamalgifb
Differential Revision: D25724176
Pulled By: anjali411
fbshipit-source-id: 16287a1f481e9475679b99d6fb45de840da225be
