Add unit test on export_opnames with interface. (#31531)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/31531
As suggested by suo , add unit test on torch.jit.export_opnames with interface. A submodule is annotated as interface and assigned to an instance, and then re-assigned to another instance. Make sure the operator names are also updated.
Test Plan: Imported from OSS
Differential Revision: D19539129
Pulled By: iseeyuan
fbshipit-source-id: 71a76ae7790cdd577618ca278afdb132727f08dc
