Summary:
- /status accepts new optional query parameters: db=1, redis=1, and timeout=<ms> (defaults to 10_000).
- These verify that the server can make trivial calls to DB/Redis, and that they return within the timeout.
- New HealthCheck tests simulates DB and Redis problems.
- Added resilience to Redis reconnects (helped by a test case that simulates disconnects)
- When closing Redis-based session store, disconnect from Redis (to avoid hanging tests)
Some associated test reorg:
- Move stripeTools out of test/nbrowser, and remove an unnecessary dependency,
to avoid starting up browser for gen-server tests.
- Move TcpForwarder to its own file, to use in the new test.
Test Plan: Added a new HealthCheck test that simulates DB and Redis problems.
Reviewers: georgegevoian
Reviewed By: georgegevoian
Differential Revision: https://phab.getgrist.com/D4054
