Switch to pytest.
Review Request #12103 — Created March 7, 2022 and submitted
nosetest runner has served us well for many years, but nose
itself is now unmaintained, and does not run on Python 3.10. We've been
migrating all our projects over to use
pytestas the test runner. This
change does that for RBTools, and fixes up a few small test-related
issues with asserts and skips.
Ran unit tests.