make vendor match with this implementation (#36302)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/36302
used 1/sqrt(x) vs rsqrt(x)
Test Plan:
tested with the seed from testwarden 1586230820
tested without the seed
Differential Revision: D20939672
fbshipit-source-id: c7be030c4ae42e78765edda2ce1ad2e213a46030
