YARN-7116. CapacityScheduler Web UI: Queue's AM usage is always show on per-user's AM usage. Contributed by Wangda Tan.

(cherry picked from commit f9e0cc8cdca387bf2811c07beccae4af07362952)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/CapacitySchedulerPage.java

@@ -228,9 +228,10 @@ class CapacitySchedulerPage extends RmView {
           resourcesUsed = userInfo.getResourceUsageInfo()
               .getPartitionResourceUsageInfo(nodeLabel).getUsed();
         }
-        ResourceInfo amUsed = (resourceUsages.getAmUsed() == null)
-            ? new ResourceInfo(Resources.none())
-            : resourceUsages.getAmUsed();
+        ResourceInfo amUsed = userInfo.getAMResourcesUsed();
+        if (amUsed == null) {
+          amUsed = new ResourceInfo(Resources.none());
+        }
         String highlightIfAsking =
             userInfo.getIsActive() ? ACTIVE_USER : null;
         tbody.tr().$style(highlightIfAsking).td(userInfo.getUsername())