RFR: 8188055: (ref) Add Reference.refersTo predicate

[Kim Barrett]

> On Apr 9, 2020, at 11:31 AM, Paul Sandoz <paul.sandoz at oracle.com> wrote:
> 
> Reference.java
> —
> 
> 335      *
> 336      * @return   The object to which this reference refers, or
> 337      *           {@code null} if this reference object has been cleared
> 
> Add @see refersTo
> 
> 338      */
> 339     @HotSpotIntrinsicCandidate
> 340     public T get() {

Thanks.  Changed locally; waiting for other discussions to converge before posting any new webrevs.