Deliver events in qtestmouse

Deliver events in qtestmouse

Not waiting until the QPA event queue is processed after
handleMouseEvent() is wrong. Unlike the synchronous sendEvent() calls
these tests most likely utilized earlier, many of the
QWindowSystemInterace functions are asynchronous in the sense that they
just queue the event, delivery will happen when the event dispatcher on
the main thread gets there.

Change-Id: I8197d2dc4805cda684a8279ceb8d4b317f19aba7
Reviewed-by: Michael Brasser <michael.brasser@nokia.com>
Reviewed-by: Jason McDonald <jason.mcdonald@nokia.com>