Get rid of extract_cwarp. (#25356)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/25356
It's no longer used.
Test Plan: Imported from OSS
Differential Revision: D17101572
Pulled By: gchanan
fbshipit-source-id: 7afb15b2f870601a773c946b8b3029bbe0a774ea
