RFR: Merge latest upstream jdk/jdk

[Roman Kennke]

Turns out I need the following additional changes to run
TestReferenceCAS with new code:

http://cr.openjdk.java.net/~rkennke/upstream-jdk12-merge-2018-10-25/webrev.00/

Ok?

Roman

> On 10/25/2018 06:22 PM, Roman Kennke wrote:
>> Highlights:
>> 8212186: JVMTI lacks a few GC barriers/hooks
>> 8212603: Need to step over GC barriers in Node::eqv_uncast()
>> 8212611: Small collection of simple changes from shenandoah
>>
>> Applied cleanly.
>> Testing: tier3_gc_shenandoah
>>
>> http://cr.openjdk.java.net/~rkennke/upstream-jdk12-merge-2018-10-25/outgoing.txt
> 
> OK!
> 
> -Aleksey
>