6805775: LinkedBlockingQueue Nodes should unlink themselves before becoming garbage
6815766: LinkedBlockingQueue's iterator can return null if drainTo(c) executes concurrently
Summary: Faster, more correct. Use self-linking trick to avoid gc retention
Reviewed-by: martin, dholmes
6785442: ConcurrentLinkedQueue.remove() and poll() can both remove the same element
6493942: ConcurrentLinkedQueue.remove sometimes very slow
Summary: new algorithm for handling concurrent linked lists
Reviewed-by: martin