fix(unitTest): shutdown thread pools and timers

Author: zhang0125

framework/src/main/java/org/tron/core/db/Manager.java

@@ -1907,6 +1907,7 @@ public NullifierStore getNullifierStore() {
   public void closeAllStore() {
     logger.info("******** Begin to close db. ********");
     chainBaseManager.closeAllStore();
+    validateSignService.shutdown();
     logger.info("******** End to close db. ********");
   }
 

framework/src/main/java/org/tron/core/net/messagehandler/TransactionsMsgHandler.java

@@ -53,6 +53,7 @@ public void init() {
   }
 
   public void close() {
+    trxHandlePool.shutdown();
     smartContractExecutor.shutdown();
   }
 

framework/src/main/java/org/tron/core/net/service/nodepersist/NodePersistService.java

@@ -27,9 +27,10 @@ public class NodePersistService {
 
   private ChainBaseManager chainBaseManager = ChainBaseManager.getInstance();
 
-  private Timer nodePersistTaskTimer = new Timer("NodePersistTaskTimer");
+  private Timer nodePersistTaskTimer;
 
   public void init() {
+    nodePersistTaskTimer = new Timer("NodePersistTaskTimer");
     if (isNodePersist) {
       nodePersistTaskTimer.scheduleAtFixedRate(new TimerTask() {
         @Override