test:
[sig-instrumentation] Prometheus when installed on the cluster shouldn't report any alerts in firing state apart from Watchdog and AlertmanagerReceiversNotConfigured [Early] 

is failing frequently in CI, see search results:
https://search.ci.openshift.org/?maxAge=168h&context=1&type=bug%2Bjunit&name=&maxMatches=5&maxBytes=20971520&groupBy=job&search=%5C%5Bsig-instrumentation%5C%5D+Prometheus+when+installed+on+the+cluster+shouldn%27t+report+any+alerts+in+firing+state+apart+from+Watchdog+and+AlertmanagerReceiversNotConfigured+%5C%5BEarly%5C%5D


sample job:
https://prow.ci.openshift.org/view/gs/origin-ci-test/logs/release-openshift-origin-installer-e2e-azure-4.6/1339620214974713856

output:
fail [github.com/openshift/origin/test/extended/util/prometheus/helpers.go:174]: Expected
    <map[string]error | len:1>: {
        "ALERTS{alertname!~\"Watchdog|AlertmanagerReceiversNotConfigured|PrometheusRemoteWriteDesiredShards\",alertstate=\"firing\",severity!=\"info\"} >= 1": {
            s: "promQL query: ALERTS{alertname!~\"Watchdog|AlertmanagerReceiversNotConfigured|PrometheusRemoteWriteDesiredShards\",alertstate=\"firing\",severity!=\"info\"} >= 1 had reported incorrect results:\n[{\"metric\":{\"__name__\":\"ALERTS\",\"alertname\":\"TargetDown\",\"alertstate\":\"firing\",\"job\":\"cluster-monitoring-operator\",\"namespace\":\"openshift-monitoring\",\"service\":\"cluster-monitoring-operator\",\"severity\":\"warning\"},\"value\":[1608228280.417,\"1\"]}]",
        },
    }
to be empty