Limit caching pods per owner reference

cluster-autoscaler/core/equivalence_groups.go

cluster-autoscaler/core/equivalence_groups_test.go

cluster-autoscaler/core/filter_out_schedulable.go

cluster-autoscaler/core/utils/pod_schedulable.go

cluster-autoscaler/core/utils/pod_schedulable_test.go

cluster-autoscaler/metrics/metrics.go