[JIT] Factor out aliases to separate test (#38746)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/38746
Factors out testing of op alias normalization so that there is a registry used for tests.
Test Plan: Imported from OSS
Differential Revision: D21673107
Pulled By: eellison
fbshipit-source-id: e06653cdf24f14a4253dd054e4d402d171d16a11
