Currently, this test can fail with the not-very-helpful [1,2]:

  fail [k8s.io/kubernetes/test/e2e/upgrades/apps/job.go:58]: Expected
      <bool>: false
  to be true

Since this test is the only CheckForAllJobPodsRunning consumer, and
has been since CheckForAllJobPodsRunning landed in 116eda09
(Implements an upgrade test for Job, 2017-02-22, #41271), this commit
refactors the function to EnsureJobPodsRunning, dropping the opaque
boolean, and constructing a useful error summarizing the divergence
from the expected parallelism and the status of listed Pods.

Thanks to Maciej Szulik for the fixups [3] :).

[1]: https://storage.googleapis.com/origin-ci-test/logs/release-openshift-origin-installer-e2e-aws-upgrade/1434/build-log.txt
[2]: https://bugzilla.redhat.com/show_bug.cgi?id=1708454#c0
[3]: https://github.com/wking/kubernetes/pull/1