pan/midgard + OpenCL: lower sizes to prevent (some) crashes

What does this MR do and why?

• before: https://gitlab.freedesktop.org/dh/mesa/-/jobs/62875796
• after: https://gitlab.freedesktop.org/dh/mesa/-/jobs/63022148

# before, mostly due assert "Invalid UBO read size":
Pass: 741, Fail: 278, Crash: 431, Skip: 82
# after (panfrost/midgard: Support 64bit pack/unpack):
Pass: 2649, Fail: 588, Crash: 106, Skip: 82, Timeout: 4
# after (panfrost/midgard: Implement vec8/16 lowering):
Pass: 2933, ExpectedFail: 534 (no details, as there is already CI-expectations in place), generally UnexpectedImprovement: 165

Second thing which this MR doing is adding nightly run, so we can track regressions.

NOTE: I don't have any T860 device with me, so I cannot debug impact of dh/mesa@01b28ab6 . It helps in come cases thou brings some regressions...