[pruner] generalize bias hook for conv2d (#62430)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/62430
The bias hook is a forward hook that is part of the pruning parametrization; it is attached after the activation reconstruction forward hook, so adding the bias occurs after zeros are reinserted to the pruned activation.
This diff/PR amends the bias hook to work for Conv2d layers, in addition to Linear layers. The reshaping of the ._bias parameter ensures that it is added to the right dimension of the output.
ghstack-source-id: 135097700
Test Plan:
Added tests for `Conv2dB()`, a model with Conv2d layers that have `bias=True`.
`buck test mode/dev-nosan //caffe2/test:ao -- TestBasePruner`
https://pxl.cl/1MfgL
Reviewed By: jerryzh168
Differential Revision: D29979571
fbshipit-source-id: c1a7e9fabc8b3c9d0050bd6b6c6a631ddfdf2a68
