When this code was using QByteArray, whose data() is never nullptr,
the strings presented to the underlying C APIs were always valid NTSs
(nullptr is not a valid NTS).
With QByteArrayView, or with QT5_NULL_STRINGS != 1, this is no longer
the case. Check that all implementations are fine with that.
Pick-to: 6.5 6.4
Change-Id: I78251288a4784440af4a2daf095aed7c53867287
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
96dc4acb23