RFR(M): Shenandoah string dedup support

[Zhengyu Gu]

On 08/24/2017 10:40 AM, Roman Kennke wrote:

>>
>> We need to suspend g1StringDedupThread, anyway to do so without
>> suspending GC threads?
> If (! ShenandoahSuspendibleWorkers), we never register any GC thread to
> the suspendible thread sets, i.e. the string dedup thread would be the
> only one. Which means we're probably ok? Can you check this?
> 
> If yes, then please push!

Confirmed and pushed.

-Zhengyu

> 
> Roman
>