testing: stress test library startup and shutdown

Internally at Lyft, we have had infrequent reports about the library getting wedged.

Via @mattklein123 :

> I was wondering if there was a way to create a small stress test that either uses the emulators or just the JVM target, and tries to do thousands of startups and shutdowns while making requests to look for failures

This is possible, and could be scheduled via github actions as a daily task.