RFR (S) 8246097: Shenandoah: limit parallelism in CLDG root handling

[Zhengyu Gu]

Looks good.

-Zhengyu

On 6/1/20 6:38 AM, Aleksey Shipilev wrote:
> RFE:
>    https://bugs.openjdk.java.net/browse/JDK-8246097
> 
> See the details in the RFE.
> 
> Webrev:
>    https://cr.openjdk.java.net/~shade/8246097/webrev.02/
> 
> Testing: hotspot_gc_shenandoah, benchmarks.
>