RFR (8u) Changed claim count to jint

[Roman Kennke]

Am 05.10.2017 um 17:33 schrieb Zhengyu Gu:
> Changed claim counter from jlong to jint to avoid nasty 
> Atomic::add(jlong, jlong*) bug, which returns old value, instead of 
> updated value (as comment stated).
>
> It is unlikely the number of regions can overflow max int, and avoid 
> using jlong, in case of fixing it in future release, that can break us 
> again.
>
> http://cr.openjdk.java.net/~zgu/shenandoah/verf_count_jint/webrev.00/
>
>
> Test:
>
>   hotspot_gc_shenandoah fastdebug in VBox where the problem was 
> discovered.
>
Good catch. Oh man...
please push!