7003434: test/closed/java/awt/FullScreen/DisplayChangeVITest/DisplayChangeVITest.java fails with ClassCastExc

Reviewed-by: jgodinez, prr
diff --git a/jdk/src/windows/classes/sun/java2d/opengl/WGLVolatileSurfaceManager.java b/jdk/src/windows/classes/sun/java2d/opengl/WGLVolatileSurfaceManager.java
index ba655bf..7c4fde1 100644
--- a/jdk/src/windows/classes/sun/java2d/opengl/WGLVolatileSurfaceManager.java
+++ b/jdk/src/windows/classes/sun/java2d/opengl/WGLVolatileSurfaceManager.java
@@ -133,7 +133,9 @@
 
     @Override
     protected boolean isConfigValid(GraphicsConfiguration gc) {
-        return ((gc == null) || (gc == vImg.getGraphicsConfig()));
+        return ((gc == null) ||
+                ((gc instanceof WGLGraphicsConfig) &&
+                 (gc == vImg.getGraphicsConfig())));
     }
 
     @Override