YARN-7385. TestFairScheduler#testUpdateDemand and TestFSLeafQueue#testUpdateDemand are failing with NPE (yufeigu via rkanter)

(cherry picked from commit 03af442e7608db2f8e6eb85a15aa0ba42781edab)

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

@@ -88,6 +88,7 @@ public class TestFSLeafQueue extends FairSchedulerTestBase {
 
     FSAppAttempt app = mock(FSAppAttempt.class);
     Mockito.when(app.getDemand()).thenReturn(maxResource);
+    Mockito.when(app.getResourceUsage()).thenReturn(Resources.none());
 
     schedulable.addAppSchedulable(app);
     schedulable.addAppSchedulable(app);

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

@@ -5249,8 +5249,10 @@ public class TestFairScheduler extends FairSchedulerTestBase {
 
     FSAppAttempt app1 = mock(FSAppAttempt.class);
     Mockito.when(app1.getDemand()).thenReturn(maxResource);
+    Mockito.when(app1.getResourceUsage()).thenReturn(Resources.none());
     FSAppAttempt app2 = mock(FSAppAttempt.class);
     Mockito.when(app2.getDemand()).thenReturn(maxResource);
+    Mockito.when(app2.getResourceUsage()).thenReturn(Resources.none());
 
     QueueManager queueManager = scheduler.getQueueManager();
     FSParentQueue queue1 = queueManager.getParentQueue("queue1", true);