RFR: 8178813: Add test for G1 pre-barrier on dereference of weak JNI handles

[Kim Barrett]

> On May 11, 2017, at 5:57 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
> 
>> […]
>> New webrevs:
>> full: http://cr.openjdk.java.net/~kbarrett/8178813/hotspot.02/
>> incr: http://cr.openjdk.java.net/~kbarrett/8178813/hotspot.02.inc/
>> 
> 
>   looks good.
> 
> Thomas

Thanks.