Follow the pattern used to guard Private::sort() calls elsewhere in the
class.
Because QAbstractItemModel::sort() is not called in the unit test, the
content is not sorted after resetting.
[ChangeLog][QtCore][QSortFilterProxyModel] QSortFilterProxyModel
now does not emit an unnecessary layoutChanged() following a model
reset.
Change-Id: I0a36c7fbb172bdd06ecddb489c5595debbef6cb9
Reviewed-by: Milian Wolff <milian.wolff@kdab.com>
3ffcfc357d