QGuiApplication::lastCursorPosition is a QPointF, and (at least on macOS)
compares always different from the QPointF stored in the event. This
might be due to the translation from system coordinates to QPointF
introducing noise.
The result is that even a simple button press causes mouseMove events
to be delivered.
To prevent this event noise, overload equality operators for the special
QLastCursorPosition type when comparing with QPointF to explicitly use
single precision comparison.
Pick-to: 6.5 6.4 6.2
Fixes: QTBUG-111170
Change-Id: I82ea23ac9f4fa80c55c9c5c742527dd7ee74fd99
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>