[Piglit] Seperate NOTRUN and SKIP from fixes and regressions

[Dylan Baker]

This series separates the SKIP and NOTRUN status changes from fixes and
regressions and puts them into separate categories, enabled and
disabled.

This makes two workflows possible where previously only one was:
1) creating baselines that are full tests, and then using small focused
   runs to compare specific tests
2) running full comparisons, and being able to see when new tests are
   enabled or tests are disabled


Patches 1-3 add test to demonstrate current behavior or to model future
behavior

Patch 4 makes NOTRUN and SKIP a special subclass which when compared
using numerics (not == or !=) will resolve False

Patch 5 Plumbs it all in