[Bug-3187]close Heartbeat thread pool when MasterRegistry unRegistry (#3188)

* [Bug-3187]close Heartbeat thread pool when MasterRegistry unRegistry

* use shutdownNow; delete redundant code

dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/master/registry/MasterRegistry.java

@@ -19,7 +19,6 @@ package org.apache.dolphinscheduler.server.master.registry;
 import org.apache.curator.framework.CuratorFramework;
 import org.apache.curator.framework.state.ConnectionState;
 import org.apache.curator.framework.state.ConnectionStateListener;
-import org.apache.dolphinscheduler.common.Constants;
 import org.apache.dolphinscheduler.common.utils.DateUtils;
 import org.apache.dolphinscheduler.common.utils.NetUtils;
 import org.apache.dolphinscheduler.remote.utils.NamedThreadFactory;
@@ -37,8 +36,6 @@ import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 
-import static org.apache.dolphinscheduler.remote.utils.Constants.COMMA;
-
 /**
  *  master registry
  */
@@ -113,6 +110,7 @@ public class MasterRegistry {
     public void unRegistry() {
         String address = getLocalAddress();
         String localNodePath = getMasterPath();
+        heartBeatExecutor.shutdownNow();
         zookeeperRegistryCenter.getZookeeperCachedOperator().remove(localNodePath);
         logger.info("master node : {} unRegistry to ZK.", address);
     }