RFR [8]: Enable heap inspection for Shenandoah

[Roman Kennke]

Duh. Yes!

Roman

> (facepalms)
> 
> This only affects sh/jdk8u, because we have this specific getter in 8. I think we have it disabled
> before we implemented heap iteration, but never noticed during backports that 8 still has it
> protected with the additional check. It was removed in 9 with:
>   https://bugs.openjdk.java.net/browse/JDK-8077411
> 
> Fix:
> 
> diff -r 70ef3638af70 src/share/vm/gc_implementation/shenandoah/shenandoahHeap.hpp
> --- a/src/share/vm/gc_implementation/shenandoah/shenandoahHeap.hpp      Mon Nov 19 10:47:38 2018 +0100
> +++ b/src/share/vm/gc_implementation/shenandoah/shenandoahHeap.hpp      Tue Nov 27 13:05:20 2018 +0100
> @@ -524,11 +524,11 @@
>    bool card_mark_must_follow_store() const                    { return false;   }
> 
>    bool is_in_partial_collection(const void* p) shenandoah_not_implemented_return(false);
> -  bool supports_heap_inspection() const { return false; }
> +  bool supports_heap_inspection() const { return true; }
> 
>    void gc_prologue(bool b);
> 
> 
> Testing: hotspot_tier3_gc_shenandoah, jmap -histo:live
> 
> Thanks,
> -Aleksey
>