RFR: Avoid stub when calling to write-barrier from C2, remove all related code

[Aleksey Shipilev]

Just wait a sec, let Roman figure out if recent failures were caused by this patch. Maybe we'll have
to redo it, or it otherwise violates some critical assumption.

-Aleksey

On 11/20/18 11:24 AM, Roman Kennke wrote:
> If it's not otherwise useful, then yes, feel free to withdraw it.
> 
> Thanks, Roman
> 
> Am 20. November 2018 09:40:51 MEZ schrieb Roland Westrelin <rwestrel at redhat.com>:
>>
>> Should I withdraw JDK-8213528 from review upstream, then?
>>
>> Roland.