[jit] Add RRef to IValue and JIT type system (#32992)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/32992
This PR add RRef to IValue and the JIT type system.
- The RRefInterface abstract class inherit from intrusive_ptr_target,
this made the RRef class can be hold in ivalue as intrusive_ptr
- Add RRefType as a JIT type, it's a container type similar to
future type.
Test Plan: Imported from OSS
Differential Revision: D19871242
Pulled By: wanchaol
fbshipit-source-id: cb80ca32605096f9a42ef147109fb368a7c1d4d3
