8032058: [TEST_BUG] [macosx] java/awt/dnd/Button2DragTest sometimes fail

Reviewed-by: anthony, serb

test/java/awt/dnd/Button2DragTest/Button2DragTest.java

 /*
- * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2006, 2014, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -112,6 +112,7 @@ public class Button2DragTest extends Applet {
         Util.drag(robot, startPoint, endPoint, InputEvent.BUTTON2_MASK);
 
         Util.waitForIdle(robot);
+        robot.delay(500);
 
         if (dropSuccess) {
             System.err.println("test passed");