Support pipeline::expedited for skipping verify jobs

The following discussion from !3821 (merged) should be addressed:

• @kkloss started a discussion: (+1 comment)

  suggestion (non-blocking): WDYT about a skip label for verify jobs? To get faster feedback from CI and not waste resources, I commented out these tests before but that feels cumbersome to do every time.

  We could perhaps even reuse the pipelineexpedited label (but not run it on merge trains)?