fix submodule imports by importing functions directly (#79368)
Summary:
fixes two sporadic issues from missing attributes:
- breaking circular imports
- submodule not being imported explicitly
Test Plan: sandcastle
Reviewed By: ehhuang
Differential Revision: D37071652
Pull Request resolved: https://github.com/pytorch/pytorch/pull/79368
Approved by: https://github.com/ananthsub
