Populate submodules of `torch._C` to `sys.modules` recursively (#132216)
Summary:
See comment:
https://github.com/pytorch/pytorch/blob/e9d1c262756d883cc597f2791d482aced4e1cb84/torch/__init__.py#L938-L950
This PR recursively sets the submodules in the C extension to `sys.modules` (e.g., `_C._dynamo.eval_frame`).
X-link: https://github.com/pytorch/pytorch/pull/132216
Approved by: https://github.com/ezyang
Reviewed By: ZainRizvi
Differential Revision: D60638625
fbshipit-source-id: bbf2462449b2ba0f203007b5dee110b1817f40bb