Add a test case to RpcTest, check src/dst (#27322)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/27322
# Problem
Existing test cases are too symmetric, so that didn't detect this error, request sent to the wrong worker.
Because of wrong `worker_names` setup, worker0 sends request to itself, while it should had sent to worker1.
# Solution
Add a test case, letting the dst side to check if it's an request from the expected src.
ghstack-source-id: 91299312
Reviewed By: satgera
Differential Revision: D17069062
fbshipit-source-id: ef7a532dd497bfc0f0ee8446fcd5d29656aaf175
