tests: Add performance tracking framework

tests: Add performance tracking framework

This adds a performance tracking framework that can run a set of tests over
specified git revisions. The ruby script for generating the reports comes from
similar performance tracking in GEGL. The framework permits evaluating new
tests against older version of clutter.

The tests themselves go through a few hoops for disabling framerate limiting in
both mesa and clutter.

When running make check the tests will be run and lines of the form:

@ test-state: 40.51 fps

will be left in the output, a script can scrape these lines out of a build log
on a buildbot to in other ways track performance.