I'm not planning to stand mesa-swrast back up until we get Kata set up, so turn the testing back on at a reduced fraction on so that venus/llvmpipe/etc. dev can still get some coverage. I haven't turned lavapipe back on, because it is now unstable in memory model / atomics tests. Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21880>