Monitor availability of registry during upgrade tests

An the registry developer
I want e2e-upgrade jobs to monitor availability of the registry during upgrades
So that I can be sure that clients can use the registry without disruptions.

Acceptance Criteria

• A new test in openshift/origin repo.

Notes

https://github.com/openshift/origin/blob/e6b3d1ece61d7c3ab5a23151c9875e1f9ad36838/test/extended/util/disruption/controlplane/controlplane.go#L69

https://bugzilla.redhat.com/show_bug.cgi?id=1884380