Timeouts and idles are subject to the whims of the load of the machine
running the tests, as we found out with the new installed tests and
OSTree-based VM running the conformance test suite continuously.
We should be able to use a repaint function and a blocking loop that
either is terminated because we hit g_assert(), or because a flag gets
toggled once we know that the Stage has been at least painted once.
The currently enabled tests using clutter_stage_read_pixels() have been
updated to this approach.
https://bugzilla.gnome.org/show_bug.cgi?id=703476
It's the conformance test suite: there's no need to namespace the files,
just like there's no need to namespace the units.
This commit does not change the Cogl tests: they will be moved to Cogl
over time, and it's easier to do if we leave them as they are.
