Allow register float16 weight_norm on cpu and speed up test (#80600) (#80600) (#81866)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/80599
Pull Request resolved: https://github.com/pytorch/pytorch/pull/80600
Approved by: https://github.com/malfet
Test Plan: contbuild & OSS CI, see https://hud.pytorch.org/commit/pytorch/pytorch/c8d64ba5ec7ee4fb2594b00e022de611bc8f2ac4
Reviewed By: seemethere
Differential Revision: D37559049
Pulled By: albanD
fbshipit-source-id: 6a44fa9c8b898e2065cdb6b160b7279466f0dc7e
Co-authored-by: albanD (Meta Employee) <desmaison.alban@gmail.com>
