RFR (8u) Changed claim count to jint

[Aleksey Shipilev]

On 10/05/2017 05:33 PM, Zhengyu Gu wrote:
> 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/

OK. Thanks for fixing this!

I'd spell that idiomatically:

     assert(_heap->num_regions() < (size_t)max_jint, "Too many regions");

-Aleksey