From in-person code review with Amir:
* getConnectionRef() has been deprecated in favor of getConnection()
* 'watchlist' query group no longer exists (T263127)
* Since this simplifies things, we can remove our wrapper methods
Change-Id: Ic610233b2e6d6ed68f7e1f5b31bb8996ed77f04b
From in-person code review with Amir: using tableExists() is a bad
idea, because the table might not consistently exists on all replicas.
It's better to have a config option despite the inconvenience.
Bug: T315353
Change-Id: I728759634c454c0dcbdc4603c15cab60415c7c03
