[BE] Enable C++ stacktraces for MultiProcessTestCase (#69175)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/69175
Shows C++ stacktraces for python distributed tests that inherit from
MultiProcessTestCase. Closes https://github.com/pytorch/pytorch/issues/69168
ghstack-source-id: 145085858
Test Plan: CI
Reviewed By: H-Huang
Differential Revision: D32736872
fbshipit-source-id: 743e870eefa7a9e77c5791d0936e2ebd5c9b1016
