As with QHoverEvent, it's better to require globalPos rather than
"initialized to QCursor::pos(), which may not be appropriate" as the
docs have pointed out for many years now. This removes the remaining
calls to QCursor::pos() in event constructors.
Task-number: QTBUG-52430
Task-number: QTBUG-69433
Task-number: QTBUG-100324
Change-Id: I076dae56f37abaad7085cc95dddee453a80a45f3
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>