<AWT Dev> [8] Review request for 7192887 java/awt/Window/Grab/GrabTest.java still failed (fix failed for CR 7149068)

[Denis S. Fokin]

bug: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7192887
webrev: http://http://cr.openjdk.java.net/~denis/7192887/webrev

UngrabEvent is not sent on some platforms (XToolkit) on window disposal. 
I have added the code in XWindowPeer.dispose() method.

We do the similar posts on EDT in XWindowPeer but I do not think that 
extraction the code in a method is needed here.

Thank you,
    Denis.