static <E> Node<E> newNode(E item) {
        Node<E> node = new Node<E>();
        ITEM.set(node, item);
        return node;
    }
static < E > Node < E > newNode ( E item ) { Node < E > node = new Node < E > ( ) ; ITEM . set ( node , item ) ; return node ; }
Returns a new node holding item.  Uses relaxed write because item
can only be seen after piggy-backing publication via CAS.