8378153: Robot.getPixelColor() may return stale pixels due to missing Toolkit.sync()

Reviewed-by: prr, azvegint

Author: mrserb

src/java.desktop/share/classes/java/awt/Robot.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2026, 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
@@ -459,6 +459,9 @@ private static void checkKeycodeArgument(int keycode) {
      * @return  Color of the pixel
      */
     public synchronized Color getPixelColor(int x, int y) {
+        // need to sync the toolkit prior to grabbing the pixels since in some
+        // cases rendering to the screen may be delayed
+        Toolkit.getDefaultToolkit().sync();
         Point point = peer.useAbsoluteCoordinates() ? toDeviceSpaceAbs(x, y)
                                                     : toDeviceSpace(x, y);
         return new Color(peer.getRGBPixel(point.x, point.y));