Remove codegen for old RegistrationDeclarations.h (#46370)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/46370
Test Plan: Imported from OSS
Reviewed By: ezyang
Differential Revision: D24324546
Pulled By: ailzhang
fbshipit-source-id: 6dea28c0c7ab5d00f8887735c32304f1b68bf923
