RFR (XS): 8212753: Improve oopDesc::forward_to_atomic

[Kim Barrett]

> On Oct 23, 2018, at 7:03 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
> 
> http://cr.openjdk.java.net/~tschatzl/8212753/webrev.0_to_1 (diff)
> http://cr.openjdk.java.net/~tschatzl/8212753/webrev.1/ (full)
> 
> Thanks,
>  Thomas

Looks good.