update timer

core/src/main/java/com/taobao/arthas/core/server/ArthasBootstrap.java

@@ -321,6 +321,7 @@ public class ArthasBootstrap {
     }
 
     public void destroy() {
+        timer.cancel();
         if (this.tunnelClient != null) {
             try {
                 tunnelClient.stop();

core/src/main/java/com/taobao/arthas/core/shell/system/impl/GlobalJobControllerImpl.java

@@ -41,7 +41,6 @@ public class GlobalJobControllerImpl extends JobControllerImpl {
 
     @Override
     public void close() {
-        timer.cancel();
         jobTimeoutTaskMap.clear();
         for (Job job : jobs()) {
             job.terminate();