RFR [11]: Revert ClassLoaderDataGraphKlassIteratorStatic to upstream version

[Roman Kennke]

Yup

> http://cr.openjdk.java.net/~shade/shenandoah/11-cleanup-cld/webrev.01/
> 
> Spotted this in our sh/jdk11 webrev. We have cleaned this up in sh/jdk:
>   http://hg.openjdk.java.net/shenandoah/jdk/rev/26c2badedf17#l3.1
> 
> ...but this never got into sh/jdk11.
> 
> Testing: tier3_gc_shenandoah, eyeballing webrev against upstream
> 
> Thanks,
> -Aleksey
>