[Distributed] Adding Python tests for the TCPStore getNumKeys and deleteKey (#45223)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/45223
Previous diffs in this stack implemented the getNumKeys and deleteKey
APIs in the c10d Store as well as added tests at the C++ layer. This diff adds
tests at the Python level in test_c10d.py
ghstack-source-id: 112939763
Test Plan: Ensured these new python tests as well as previous C++ tests pass
Reviewed By: jiayisuse
Differential Revision: D23878455
fbshipit-source-id: 0a17ecf66b28d46438a77346e5bf36414e05e25c
