YARN-11656 RMStateStore event queue blocked

- fix out of array exception

Author: K0K0V0K

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/event/multidispatcher/MultiDispatcherExecutor.java

@@ -57,7 +57,7 @@ public MultiDispatcherExecutor(
 
   public void execute(Event event, Runnable runnable) {
     String lockKey = event.getLockKey();
-    int threadIndex = lockKey == null ? 0 : lockKey.hashCode() % threads.length;
+    int threadIndex = lockKey == null ? 0 : Math.abs(lockKey.hashCode()) % threads.length;
     MultiDispatcherExecutorThread thread = threads[threadIndex];
     thread.add(runnable);
     LOG.debug("The {} with lock key {} will be handled by {}",