In 4e400369c0 we began to send synth-mouse
events from the touch device, but in the opposite direction it was not
consistent.
Add autotests to prove that it's consistent both ways now.
Change-Id: I7df2328fef224dc1529ca5d27411cd8a5a9c8df9
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>