winemac: Don't post a WINDOW_BROUGHT_FORWARD event for a click on a window which is already frontmost in its level.

Commit 793ab7d4 fixed a bug where WINDOW_BROUGHT_FORWARD events weren't being
posted when they should, but it caused a regression in Scribblenauts Unlimited.
Every click caused a window ordering operation that generated messages and
Scribblenauts would move the mouse cursor to the upper-left corner of the
window in response.
Signed-off-by: Ken Thomases <ken@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>