[RPC tests] Fix test_init_(rpc|pg)_then_(rpc|pg) not shutting down RPC (#41558)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/41558
The problem was due to non-deterministic destruction order of two global static variables: the mutexes used by glog and the RPC agent (which was still set because we didn't call `rpc.shutdown()`). When the TensorPipe RPC agent shuts down some callbacks may fire with an error and thus attempt to log something. If the mutexes have already been destroyed this causes a SIGABRT.
Fixes https://github.com/pytorch/pytorch/issues/41474
ghstack-source-id: 108231453
Test Plan: Verified in https://github.com/pytorch/pytorch/issues/41474.
Reviewed By: fmassa
Differential Revision: D22582779
fbshipit-source-id: 63e34d8a020c4af996ef079cfb7041b2474e27c9
