RFR: Purge some G1-related cruft in C2

[Roman Kennke]

Am 11.09.2018 um 22:25 schrieb Aleksey Shipilev:
> On 09/11/2018 10:13 PM, Roman Kennke wrote:
>> This gets rid of Node::is_g1_marking_load() and Node::is_g1_marking_if()
>> .. some fairly obvious leftovers from GC-interface-ification, and fixed
>> related call-sites. This is closer to upstream and arguably/hopefully
>> more correct.
>>
>> http://cr.openjdk.java.net/~rkennke/purge-c2-cruft/webrev.00/
> 
> *) The change to is_shenandoah_marking_load in ShenandoahWriteBarrierNode::fix_ctrl looks like a
> bugfix, please split it out in a separate changeset, so we are sure it is backported even if other
> cleanups are not?
> 
> Otherwise looks good.

Right. RFR'ed in another thread.

http://cr.openjdk.java.net/~rkennke/purge-c2-cruft/webrev.01/

Ok?

Roman