Commit 4a40c717f3 optimized
QString::compare_helper(QChar*, int, char*, int), but got
the case wrong where the rhs is null, but the lhs is empty,
not null (which is the case even with a null QString, as
QString().constData() != nullptr). The correct result in
this case is 0, since in Qt empty and null strings compare
equal.
Fix by checking the length of lhs, not its pointer.
Task-number: QTBUG-55154
Change-Id: I3ec2cd25d9bdca90cf3f5568a875b1e52c779979
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>