[rpc] use annotation_str for RRef type serialization (#39932)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/39932
This PR make RRef fork to use the jit type annotation_str recently introduce in
https://github.com/pytorch/pytorch/pull/39544 to allow consistent
serialization type str format, and fix the case when dict->str() format
not match the type resolver.
Test Plan: Imported from OSS
Differential Revision: D22015427
Pulled By: wanchaol
fbshipit-source-id: f64d7e3acde5312813816c8f3c7d8fa9379704e8
