The KDE window manager kwin launches window overview, when the mouse
remains in the top left for about 1 second. This causes flakiness in
autotests, if they move the mouse to the top left.
=> Disable the overview function, which is enabled by default.
Change-Id: I43925d15db99f5d40b6cc0cdba39203513e8c59f
Reviewed-by: Toni Saario <toni.saario@qt.io>
