RFR (S/M): 8225478: Make G1CMRootRegions independent of HeapRegions

[Kim Barrett]

> On Jun 11, 2019, at 9:23 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
> http://cr.openjdk.java.net/~tschatzl/8225478/webrev.0_to_1 (diff)
> http://cr.openjdk.java.net/~tschatzl/8225478/webrev.1 (full)
> 
> Testing: local compilation
> 
> Thanks,
>  Thomas

Looks good.