[pruner] add handles for hooks (#61425)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/61425
Adding handle for activation reconstruction and bias forward hooks so they can be removed later
ghstack-source-id: 133244536
Test Plan:
This change should not affect behavior yet, but to double check:
`buck test mode/dev-nosan //caffe2/test:ao -- TestBasePruner`
https://pxl.cl/1LpM9
Reviewed By: z-a-f
Differential Revision: D29619720
fbshipit-source-id: c7428d2d0325cd11ce7919e0b67321e8cc196041
