[JIT] Add Frozen Conv-> Add/Sub/Mul/Div fusion (#50075)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/50075
Adds Conv - Add/Sub/Mul/Div fusion for frozen models. This helps cover models like torchvision maskrcnn, which use a hand-rolled batchnorm implementation: https://github.com/pytorch/vision/blob/90645ccd0e774ad76200245e32222a23d09f2312/torchvision/ops/misc.py#L45.
I haven't tested results yet but I would expect a somewhat similar speed up as conv-bn fusion (maybe a little less).
Test Plan: Imported from OSS
Reviewed By: tugsbayasgalan
Differential Revision: D25856265
Pulled By: eellison
fbshipit-source-id: 2c36fb831a841936fe4446ed440185f59110bf68
