[rpc] replace tests on worker_name (#35955)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/35955
bulk replace worker{} with worker_name()
Test Plan: Imported from OSS
Differential Revision: D20849012
Pulled By: wanchaol
fbshipit-source-id: 52ab1439c9dbfe814b576a97b0689331f1ff0274
