Window activation is not working reliably on X11 when combined with
X11BypassWindowManagerHint, see QXcbWindow::requestActivateWindow().
The test itself counts repaints, so qWaitForWindowExposed() shouldn't be
needed.
This way we don't need to QSKIP() the test if window activation fails.
Fixes: QTBUG-98921
Change-Id: I849b7261c757fb7cbcde73f11bbe1a74a862cb9c
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>