RFR (M) 8246340: Move SystemDictionary GC roots into OopStorage

[coleen.phillimore at oracle.com]

Offline, Erik pointed out that I missed a system_dictionary tag in 
parallelGC and to not initialize OopStorage static data members, so 
here's an incremental that I reran tier1 tests on.

open webrev at 
http://cr.openjdk.java.net/~coleenp/2020/8246340.02.incr/webrev

Thanks,
Coleen

On 6/3/20 1:23 PM, coleen.phillimore at oracle.com wrote:
> Summary: use vm_global() OopStorage for system dictionary roots 
> removed SystemDictionary::oops_do in all the GCs.
>
> Tested with tier1-6.
>
> open webrev at http://cr.openjdk.java.net/~coleenp/2020/8246340.01/webrev
> bug link https://bugs.openjdk.java.net/browse/JDK-8246340
>
> Thanks,
> Coleen