ci: More context for color_clear and render skips for Wayland
- Add some more context and notes from testing with llvmpipe, freedreno and zink-on-turnip
- Explicitly list skips.. I didn't run enough times to rule out flakes, but I didn't see any with local testing
- Remove per-driver xfails/flakes. No point in someone spending time trying to track down a non-existent driver bug without realizing that it isn't something driver specific.
/cc @dh