Update tests to not use deprecated base classes.
Review Request #12104 — Created March 7, 2022 and submitted
We had renamed the test base classes to be more consistent, but never
updated most of our test cases to inherit from the new versions. This
wasn't noticed because our old test runner didn't print warnings, but
pytest does. This change moves everything inside RBTools over to the new
names. I've also fixed up a couple calls to the deprecated
Ran unit tests and saw everything complete with no warnings.