The documentation says that if it's negative, we find the null
termination. This bug was introduced with the clean up to use
QByteArrayView in commit 8897aa071a.
Fixes: QTBUG-99640
Pick-to: 6.3 6.2
Change-Id: Ib42b3adc93bf4d43bd55fffd16c89fa4a960f3a9
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Marc Mutz <marc.mutz@qt.io>