[Piglit] Cleanups for framework unit tests

[Dylan Baker]

This series is purely focused on the frameworks/tests directory, unit
tests for the python framework.

Largely this work is about making the unit tests identify what function
or class or method they're testing (they don't currently which makes
them annoying to use). There are a few patches in here that remove
duplicate tests, or simplify some over-engineered machinery, or make use
of functions in the utils module, as well as a couple of cleanups to the
utils module itself.

This results in zero functional change outside of the unit tests, so I
doubt anyone but me even cares. I've sent this out just in case someone
does, but I plan to merge this in the next couple of days because it
isn't going to effect anyone else, but it will make things easier for
me.