Add WorkerInfo through TorchBind to make it an available type in TorchScript (#35447)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/35447
as titled
Test Plan:
```
buck test mode/dev-nosan //caffe2/test/distributed/rpc/jit:rpc_fork
buck build mode/dev-nosan //caffe2/test/distributed/rpc/jit:rpc_fork && \
buck-out/gen/caffe2/test/distributed/rpc/jit/rpc_fork\#binary.par \
-r test_return_local_script_class_rref_in_py_and_use_in_script
```
Differential Revision: D7923053
fbshipit-source-id: 7b80e0b28aa66343249b8af328ba251314674dcc
