[Performance][PeerTaskInstancePriorityQueue]code style formatter

dolphinscheduler-service/src/main/java/org/apache/dolphinscheduler/service/queue/PeerTaskInstancePriorityQueue.java

@@ -24,7 +24,6 @@ import java.util.Comparator;
 import java.util.Iterator;
 import java.util.PriorityQueue;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.locks.Condition;
 import java.util.concurrent.locks.ReentrantLock;
 
 /**
@@ -47,11 +46,6 @@ public class PeerTaskInstancePriorityQueue implements TaskPriorityQueue<TaskInst
      */
     private final ReentrantLock lock = new ReentrantLock(true);
 
-    /**
-     * Condition for blocking when empty
-     */
-    private final Condition notEmpty = lock.newCondition();
-
     /**
      * put task instance to priority queue
      *