Request to backport fix for 6708392 to openjdk6

[Martin Buchholz]

Hi SunToolkit.setOverrideRedirect team,

Google engineers have found that
6708392: Provide internal API to create OverrideRedirect windows, XToolkit
is a showstopper bug,
(for folks using NX on Windows or Mac)
and that the fix in openjdk7 fixes it,
when trivially backported to openjdk6.

Many thanks to Brian Duff for the hard work of
testing and debugging.

I'd like to commit this fix to openjdk6.

Webrev:
http://cr.openjdk.java.net/~martin/webrevs/openjdk6/SunToolkit.setOverrideRedirect/

Martin