"Leaks" utility in the Instruments app report memory leak.

On macOS, when a tooltip is activated for a control that has been assigned a tooltip, the "Leaks" utility in the Instruments app report a  memory leak.

To reproduce this:
1) Build and launch the gallery application in the qtbase/examples/widgets/gallery folder.
2) Launch the Instruments app and select the "Leaks" utility.
3) In the target selector, choose "gallery"
4) Press the "record" toolbar button (the red dot in a circle) to begin profiling leaks, then select Leaks" to see leaks in the timeline.
5) Move focus to the gallery app and wait 10 seconds to see an "inactive" status appear in the Leaks timeline.
6) Move the mouse over the tab widget control to activate a tooltip, then move the mouse away.
Notice a leak event appears in the timeline.
Each time you activate a tooltip, within 10 seconds, another leak event will appear in the timeline which will include one or more leaks.

The leak indicates a QNSViewMenuHelper is being leaked, and the callstack associated with the leak indicates it is happening during [QNSView initWithCocoaWindow] which is called during QToolTip::showText() .