[REG 5.11.2-5.12.0] QToolTip: Unwanted wrapping of plain text

The behavior of QToolTip for plain text changed in 5.12 so that text is often (unnecessarily) wrapped in multiple lines.

This seems to be caused by change https://codereview.qt-project.org/#/c/221777 , which aimed for making tooltips wrap for 'very long text'. Anyhow, the default behavior of QLabel and therefore also QToolTip is actually to wrap around much more agressively.