[NNC] added skeleton for refactoring (#55371)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/55371
Test Plan: Imported from OSS
Reviewed By: zou3519
Differential Revision: D27616418
Pulled By: Chillee
fbshipit-source-id: 8187a0cb2495b6bec07bb5992e352da3ffb299fb
