Support grabbing test suite metrics

Update the "interesting" controller-manager metrics to match the
current names for the garbage collector, and add namespace controller
metrics to the list.

hack/verify-flags/known-flags.txt

@@ -290,6 +290,7 @@ garbage-collector-enabled
 gather-logs-sizes
 gather-metrics-at-teardown
 gather-resource-usage
+gather-suite-metrics-at-teardown
 gce-multizone
 gce-project
 gce-service-account