Merge branch 'pb/ci-matrix-wo-shortcut' into maint

Our setting of GitHub CI test jobs were a bit too eager to give up once there is even one failure found. Tweak the knob to allow other jobs keep running even when we see a failure, so that we can find more failures in a single run. * pb/ci-matrix-wo-shortcut: ci: do not cancel all jobs of a matrix if one fails