Create prototype for AST rewriter (#46410)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/46410
Test Plan: Imported from OSS
Reviewed By: SplitInfinity
Differential Revision: D24665950
Pulled By: ansley
fbshipit-source-id: b72110436126a24ddc294b8ee7b3f691281c1f1b
