private int reverseCountElements() {
            int n = 0;
            for (final Iterator<String> j = l.reverseIterator(); j.hasNext(); j.next()) {
                ++n;
            }
            return n;
        }
Check we keep the consistent view when reading and writing in parallell.

@author Steinar Knutsen
vespajlib/src/test/java/com/yahoo/concurrent/ThreadRobustListTestCase.java