For consistency with append and prepend we should have an overload for
insert() as well. This also enables insert() to be used with
QStringBuilder, i.e. qba.insert(2, qba2 + "abc").
Because simply adding a const QByteArray & overload causes ambiguity
with QByteArrayView we also add a const char * overload.
Add some extra test-cases. Two for QByteArrayView since it's not
directly tested anymore. One for inserting self directly.
Change-Id: Ieb43a6a7d1afbb498bc89c690908d7f0faa94687
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>