Add fuse support for batchnorm with affine=False (#45474)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/45474
When batchnorm affine is set to false, weight and bias is set to None, which is not supported in this case. Added a fix to set weights to 1 and bias to 0 if they are not set.
Test Plan: Add unit test for testing fusing conv, batchnorm where batchnorm is in affine=False mode.
Reviewed By: z-a-f
Differential Revision: D23977080
fbshipit-source-id: 2782be626dc67553f3d27d8f8b1ddc7dea022c2a
