RFR (sh/jdk11): Follow-up fixes and cleanups for Shenandoah SATB

[Zhengyu Gu]

Good to me.

Thanks,

-Zhengyu

On 12/17/19 5:09 AM, Roman Kennke wrote:
> This fixes two issues:
> - Rename SATBMarkQueue -> ShenandoahSATBMarkQueue in aarch64 code
> - Remove obsolete G1CollectedHeap::requires_marking()
> 
> http://cr.openjdk.java.net/~rkennke/shjdk11-satb-followup/webrev.00/
> 
> Testing: hotspot_gc_shenandoah
> 
> Ok?
> 
> Roman
>