RFR 9: 8145459 Cleaner - use Reference.reachabilityFence

[Paul Sandoz]

> On 20 Jan 2016, at 16:14, Roger Riggs <Roger.Riggs at Oracle.com> wrote:
> 
> Please review this update to the Cleanable implementations to use Reference.reachabilityFence:
> 
> Webrev:
>   http://cr.openjdk.java.net/~rriggs/webrev-fence-8145459/
> 

Yay, +1

Paul.