broadcom/ci: fix default timeout and timeout of v3d-rpi4-gl:arm32
broadcom/ci: set default TEST_PHASE_TIMEOUT_MINUTES so that jobs never timeout without uploading results
The CI-wide default is 20min, so if we set a 20min job timeout here, we
can't get the results of our jobs when they timeout.
Instead of setting the test timeout to 15min, which would be too short
for some jobs, leave it at 20min (but be explicit about it and protect
against a future change of that default), and bump the job timeout by
5min to allow for results to be uploaded.
broadcom/ci: increase the timeout of the nightly job v3d-rpi4-gl:arm32 by 10min
+5min might be enough but let's have 5 more minutes of margin.
Second commit is because v3d-rpi4-gl:arm32
has timed out a few times now, eg. https://gitlab.freedesktop.org/mesa/mesa/-/jobs/62327735
First commit was noticed because that job timing out would have looked different, as it would not have prevented the results from being uploaded if the default test & job timeouts had that margin.