public void sort() {
        if (hitOrderer == null) {
            Collections.sort(hits);
            hitsSorted = true;
        } else if (sortableWithSortData()) {
            SortDataHitSorter.sort(this, hits);
            hitsSorted = true;
        } else {
            // This may or may not lead to a sorted result set, but it's a best effort
            hitOrderer.order(hits);
            if (likelyHitsHaveCorrectValueForSortFields()) {
                hitsSorted = true;
            }
        }
    }
Force hit sorting now.
This is not normally useful because a group will stay sorted automatically,
but it is in the case where
the hits have changed their internal state in a way that should change ordering
container-search/src/main/java/com/yahoo/search/result/HitGroup.java