ci: Enable process isolation for softpipe & freedreno piglit jobs
Disabling process isolation causes a random set of tests to be spuriously skipped. The set of skipped tests can change when piglit is rebuilt (even from the same Git commit), which can make docker image rebuilds painful. (Not to mention the reduced testing coverage due to the skipped tests)
One downside of this change is that the arm64_a630_piglit_shader job now takes almost 10 minutes.
v2:
- Change arm64_a530_piglit_shader job as well, but make it run manually on branches of forked repositories only, since it takes almost 20 minutes now. (Eric Anholt)
Edited by Michel Dänzer