[Bug-5132][server] stop the take immediately if an exception occurs in the taskExecuteThread (#5133)

* [DS-5132][fix] stop the take immediately if an exception occurs in the taskExecuteThread
- let softkill() method return true when the process is stopped,else return false;

dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/worker/task/AbstractCommandExecutor.java

@@ -289,7 +289,7 @@ public abstract class AbstractCommandExecutor {
             }
         }
 
-        return process.isAlive();
+        return !process.isAlive();
     }
 
     /**