Add clock interface to disruption controller

To be able to write more precise unit tests in the future

Change-Id: I8f45947dfacca501acd856849bd978fad0f735cd

Kubernetes-commit: dad8454ebb87ba7af897537db6d34033127bbfef

util/workqueue/rate_limiting_queue.go

@@ -50,6 +50,13 @@ func NewNamedRateLimitingQueue(rateLimiter RateLimiter, name string) RateLimitin
 	}
 }
 
+func NewRateLimitingQueueWithDelayingInterface(di DelayingInterface, rateLimiter RateLimiter) RateLimitingInterface {
+	return &rateLimitingType{
+		DelayingInterface: di,
+		rateLimiter:       rateLimiter,
+	}
+}
+
 // rateLimitingType wraps an Interface and provides rateLimited re-enquing
 type rateLimitingType struct {
 	DelayingInterface