[Pytorch Mobile] Fold Conv BatchNorm for functions besides forward (#54619)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/54619
Minor refactor to conv batchnorm folding to work on other functions besides forward
ghstack-source-id: 125767010
Test Plan: unit test and {P339453712}
Reviewed By: kimishpatel
Differential Revision: D27301452
fbshipit-source-id: 4e0cc544a171a970583979a496b2908935124497
