QCoreApplication::installTranslator() does not take ownership of the
QTranslator. The QTranslator dtor removes itself from QCoreApplication
again.
Pick-to: 6.3 6.2 5.15
Change-Id: I17eb7ab350631eb32fe76af29d9a576a0efa05d8
Reviewed-by: Lars Knoll <lars.knoll@qt.io>