Cocoa: Don't activate popup windows.

Qt expects a handleWindowActivated call for non-
popup windows only. Add a window type check, similar
to the other handleWindowActivated calls.

Task-number: QTBUG-38707
Change-Id: Iaa5959675f7e3ae4664bdf785d3f374debb0d0a7
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@theqtcompany.com>
Reviewed-by: Liang Qi <liang.qi@theqtcompany.com>