Skip test-pull-repeated during CI

Skip test-pull-repeated during CI

This test is expected to fail a small proportion of the time. During
the build of ostree 2018.7-1 in Debian, it seems we were unlucky on
s390x. Non-deterministic tests are also problematic for autopkgtest,
where they can gate migration of our dependencies like GLib, so skip
this test unless the caller has opted-in to non-deterministic tests.

It would be appropriate to enable this test in environments where
failures can easily be retried and are not disruptive to other
packages.

Signed-off-by: Simon McVittie <smcv@debian.org>
Gbp-Pq: Topic debian
Gbp-Pq: Name Skip-test-pull-repeated-during-CI.patch