RFR(XXS) 8224525: Shenandoah: Eliminate shenandoah verifier's side-effects

[Zhengyu Gu]

> The idea looks good.
> 
> Let's put the comment like:
> 
>   672   // Deactivate barriers temporarily: Verifier wants plain heap accesses
>   673   ShenandoahGCStateResetter resetter;
> 
> You can common the use of ShenandoahHeap::heap() here (in fact you can probably just pull it into
> the ShenandoahGCStateResetter const field):
> 
>   618   ~ShenandoahGCStateResetter() {
>   619     ShenandoahHeap::heap()->_gc_state.set(_gc_state);
>   620     assert(ShenandoahHeap::heap()->gc_state() == _gc_state, "Should be restored");
>   621   }

Updated: http://cr.openjdk.java.net/~zgu/JDK-8224525/webrev.01/

Okay now?

Thanks,

-Zhengyu

> 
> -Aleksey
>