Merge pull request #3891 from actiontech/2399

fix IdleHeartBeat inner 2399

Author: ylinzhu

src/main/java/com/actiontech/dble/backend/datasource/PhysicalDatasource.java

@@ -253,7 +253,6 @@ private void longIdleHeartBeat(ConcurrentLinkedQueue<BackendConnection> linkedQu
                 new ConnectionHeartBeatHandler().doHeartBeat(con);
             } else {
                 linkedQueue.offer(con);
-                break;
             }
         }
     }