Fix the flake in global reconcile test. (#6879)
Fix the flake in global reconcile test. (#6879)

This is another instance of things being out of sync.
In this case sometimes the config map watch fired earlier than the informer caches were propagated,
thus nothing would get updated and the hook would never fire.
Make sure the fake informer/lister see the new ingress before we fire the cache update

Fixes #6860
knative-sandbox/net-istio,knative-sandbox/net-istio