ci: Enable NIR_VALIDATE everywhere.
I wasted a bunch of time today tracking down a spurious test results change due to a driver invoking UB by running tests where NIR validation had failed (instruction reading from components beyond vector size). If we need to shrink our coverage to get runtimes down, it will still be better to be catching validation errors in CI.
To keep the test jobs runtime under 10 minutes, I've split a530's gles2 to two different jobs.
@jekstrand who has been in favor of this in the past
Edited by Emma Anholt