GDK W32: Only restack windows with matching always-on-top status
GDK W32: Only restack windows with matching always-on-top status

This prevents normal application windows (and other kinds of windows)
from being moved up in Z-order to be above windows that have the
always-on-top bit set. Doing so would make the previously-normal windows
in question also always-on-top implicitly.
Windows that are already always-on-top will be restacked on top of other
always-on-top windows too.

https://bugzilla.gnome.org/show_bug.cgi?id=746745

grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita