Subclasses of TestCase don't need to reset conf

Subclasses of TestCase were unnecessarily resetting the config on
cleanup. This is unnecessary because TestCase resets the config
already.

This takes care of some TODOs in the code.

Change-Id: I4350efb03a40616e6a9e7fb6ee7cc507f4709f00
Merge "Subclasses of TestCase don't need to reset conf"