[REG] Wayland: Over 2x higher painting CPU usage when display scaling is used

#include <QGuiApplication>
#include <QRasterWindow>
#include <QElapsedTimer>
#include <QPainter>

class PaintWin : public QRasterWindow
{
public:
    QElapsedTimer et;

    uint8_t brightness = 0;
    int64_t cnt = 0;

    PaintWin()
    {
        QSurfaceFormat surfaceFormat;
        surfaceFormat.setAlphaBufferSize(8);
        setFormat(surfaceFormat);
        et.start();
    }

    void paintEvent(QPaintEvent *) override
    {
        auto elapsed = et.nsecsElapsed() / 1e9;
        if (elapsed >= 1.0)
        {
            et.restart();
            qDebug () << cnt / elapsed << "FPS";
            cnt = 0;
        }
        ++cnt;

        QPainter p(this);
        p.fillRect(QRect(QPoint(), size()), QColor(brightness, brightness, brightness));
        ++brightness;
        update();
    }
};

int main(int argc, char *argv[])
{
    QGuiApplication a(argc, argv);

    auto win = new PaintWin;
    win->showMaximized();

    return a.exec();
}