RFR: Add GCBasher test for Shenandoah

[Roman Kennke]

Am Montag, den 28.11.2016, 10:13 +0100 schrieb Aleksey Shipilev:
> On 11/25/2016 07:36 PM, Roman Kennke wrote:
> > This adds a test to run GCBasher with Shenandoah.
> > 
> > http://cr.openjdk.java.net/~rkennke/gcbasher/webrev.00/
> 
> Do we really want -Xmx128m there? 2/4/8 Gb seems more reasonable for
> Shenandoah.

Well, it does fit, which is a good thing in itself. I just copied what
I found for other collectors.

For larger heaps I'd also have GCBasher produce larger workloads. Let's
do that later, should we?

Roman