FastArrayList.toString() fails to check for reference to itself

FastArrayList.toString() throws a StackOverflowError when the list contains itself, because toString() is called recursively. In contrast, ArrayList checks for this case and deals with it appropriately. E.g.:

ArrayList l = new FastArrayList();
l.add(l);
l.toString(); // StackOverflowError

But:

ArrayList l = new ArrayList();
l.add(l);
l.toString(); // OK

To be compatible with its superclass, FastArrayList should also consider this special case.