Support submodule manipulation in GraphModule (#52358)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/52358
Test Plan: Imported from OSS
Reviewed By: jamesr66a
Differential Revision: D26759260
Pulled By: ansley
fbshipit-source-id: 25d2b9124a7d957704f1700a45dca143aaed391d
