updateref: Skip another known-flaky test with Git v2.33.0
In 53944694 (updateref: Skip known-flaky test with Git v2.33.0,
2022-07-08) we have started to skip a test that's known to be flaky with
Git v2.33.0 or older. While this test is not flaking anymore, we're now
regularly seeing a similar flake in another test. This new flaky test is
related to cancellation, but it also does the same Prepare()
step and
expects that to properly lock the references, which is not guaranteed by
Git v2.33.0.
Skip this test as well to decrease flakiness.
See e.g. https://gitlab.com/gitlab-org/gitaly/-/jobs/2734716996