[nnc] Fix batchnorm implementation (#64112)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/64112
Fixes #64062
Test Plan: Imported from OSS
Reviewed By: zhxchen17
Differential Revision: D30622897
Pulled By: bertmaher
fbshipit-source-id: 7d7c6131aa786e61fa1d0a517288396a0bdb1d22
