RFR (11u, XXL): Upstream/backport Shenandoah to JDK11u

[Roman Kennke]

On Thu, 2020-07-09 at 15:33 +0300, Aleksei Voitylov wrote:
> That would be awesome, thanks!
> 
> I also saw interpreter/interpreter.hpp

Yes. I could wrap it in #if INCLUDE_SHENANDOAHGC, but it's actually a
correct addition because Interpreter is used in that compilation unit.

>  and a couple of other unguarded
> modifications.

I only see some lone friend and class declarations, but they wouldn't
do anything. If it's easier to review or reduces risks I can put #if
INCLUDE_SHENANDOAHGC there too.

Cheers,
Roman