RFR: Eliminating Shenandoah exposure to CLD

[Roman Kennke]

Oh, great! Possible that this has changed due to Erik's recent conc-CLD
work. Good to push!

Thanks,
Roman


> Apparently, ParallelCLDRootIterator does not need to access any
> private/protected method/field of CLD, so can eliminate CLD from diff.
> 
> Webrev:
> http://cr.openjdk.java.net/~zgu/shenandoah/rm_cld_exposure/webrev.00/index.html
> 
> 
> 
> Test:
>   clean fastdebug and release builds with/without precompiled headers.
> 
> Thanks,
> 
> -Zhengyu