6647361: use Unsafe.put*Volatile methods to set final fields during default deserialization

[Alan Bateman]

Brian Goetz wrote:
> Is it possible to coalesce the fences so that we don't incur them on 
> every field write?
I've also been concerned about performance. As I understand it, but 
maybe I have it wrong, is that the JLS [1] doesn't allow this when 
changing final fields after an object is constructed.

-Alan.

[1] http://java.sun.com/docs/books/jls/third_edition/html/memory.html#17.5.3