RFR: Rehash allocation tests

[Zhengyu Gu]

Okay.

-Zhengyu

On 08/08/2017 12:20 PM, Aleksey Shipilev wrote:
> Our current allocation tests seem both too aggressive and too simplistic, and thus consuming
> significant time without added benefit. This change rehashes them: make them shorter, but more random:
>   http://cr.openjdk.java.net/~shade/shenandoah/tests-rehash-1/webrev.01/
>
> Testing: hotspot_gc_shenandoah
>
> Thanks,
> -Aleksey
>