YARN-5343. TestContinuousScheduling#testSortedNodes fails intermittently. (Yufei Gu via kasha)

(cherry picked from commit 7992c0b42ceb10fd3ca6c4ced4f59b8e8998e046)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/TestContinuousScheduling.java

@@ -167,8 +167,8 @@ public class TestContinuousScheduling extends FairSchedulerTestBase {
     Assert.assertEquals(2, nodes.size());
   }
 
-  private void triggerSchedulingAttempt() {
-    mockClock.tickMsec(
+  private void triggerSchedulingAttempt() throws InterruptedException {
+    Thread.sleep(
         2 * scheduler.getConf().getContinuousSchedulingSleepMs());
   }
 }