[REG 5.13 -> 5.14] No longer possible to shallow copy QVector<QPointF> to and from QML

Since https://bugreports.qt.io/browse/QTBUG-80916 was fixed there is severe performance impact when using QVector<QPointF> with QML in Qt 5.14.2 and Qt 5.15.0.

Emitting QVector<QPointF> from C++ to QML and from QML to C++ happens instantaneously in Qt 5.13.2.

Attached program 'Charting.tar.gz' track the time needed to generate QVector<QPointF> in one plugin and plot the data through another. It take ~1 millisecond to plot 10 millions points after they are generated  in Qt 5.13.2 and ~7000 milliseconds in Qt 5.14.2 and Qt 5.15.0.

Screen shot 'QVector_QPointF_regression.png' showing the program running with Qt 5.13.2, Qt 5.14.2 and Qt 5.15.0 is attached as well.