Plumbing unit tests pending

[JeromeJu]

Actual Behavior

All existing Plumbing unit tests are pending;

• Some of them passes as demonstrated on the github UI while some of them just fails while it is pending.

Prow log:
https://prow.tekton.dev/job-history/gs/tekton-prow/pr-logs/directory/plumbing-unit-tests

Prow job that passed in github UI through merged PR
https://prow.tekton.dev/view/gs/tekton-prow/pr-logs/pull/tektoncd_plumbing/1798/plumbing-unit-tests/1755259783415336960

[AlanGreene]

I think this might be a known issue related to jobs run on Tekton vs Prow. The plumbing-unit-tests jobs run on Tekton as far as I know.

I vaguely recall similar discussion about pending / leftover jobs but can't find it now, possibly lost somewhere in old Slack messages.

@afrittoli @vdemeester Do you have more background on this? Is there something we can / should do to clean these up?