The size of the texture used for test-cogl-npot-texture was only using
1 pixel of waste and the texture was scaled down so it would be quite
likely that the test would still pass if only the top left slice was
rendered. It also didn't test using non-default texture
coordinates. These problems made it fail to pick up bug 2398. The
texture is now using the maximum amount of waste and rendered in four
parts at 1:1 scale.
This greatly speeds up running all the conformance tests by no longer
delaying many of the tests for a number of dummy frames to be painted.
We used to skip frames because we thought there was a problem with the
driver's glReadPixels implementation. Although we have seen driver
issues at times the real reason the delay was needed was because
resizing the stage usually happens asynchronously (because a non
synchronous X request is used by clutter_stage_set_size()). We now force
all X requests to be synchronized for the conformance tests so this is
no longer a problem and we can avoid these hacks.