Automatic merge from submit-queue (batch tested with PRs 38377, 36365, 36648, 37691, 38339)

Do not create selector and namespaces in a loop where possible

With 1000 nodes and 5000 pods (5 pods per node) with anti-affinity a lot of CPU wasted on creating LabelSelector and sets.String (map). 

With this change we are able to deploy that number of pods in ~25 minutes. Without - it takes 30 minutes to deploy 500 pods with anti-affinity configured.