Refactor ForeachUnaryOps.cu (#49248)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/49248
Test Plan: Imported from OSS
Reviewed By: zou3519
Differential Revision: D25502940
Pulled By: izdeby
fbshipit-source-id: fce2f18a4f62f7a5fdd6747707d006c3588530d1
