Construct a -Wall around Torch (#59668)
Summary:
Removes unused variables and functions and performs other minor mods sufficient to introduce `-Wall` as a default build flag. This should enhance code safety in the future.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/59668
Test Plan: Sandcastle
Reviewed By: ngimel
Differential Revision: D28974453
fbshipit-source-id: 011c720dd6e65fdbbd87aa90bf57d67bfef32216
