Make GenLazyNativeFuncDefinition abstract and extensible (#75343)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/75343
- Rename LazyIr generator classes for consistency
- clean up dead code
Test Plan: Imported from OSS
Reviewed By: bdhirsh
Differential Revision: D35455171
Pulled By: wconstab
fbshipit-source-id: 47feaf0fc6d0f7cc383993fcf2edb17297639705
(cherry picked from commit dabda11b80db2ac9a52adf5fb7926098040f7ff0)
