RFR: JVMStat heap region counters

[Aleksey Shipilev]

On 12/14/2016 04:29 PM, Roman Kennke wrote:
> http://cr.openjdk.java.net/~rkennke/regioncounters/webrev.00/

*) I kinda crammed things into ShenandoahConcurrentThread. We can do:

  heap->monitoring_support()->update_counters();

...once after the if.

Otherwise looks good.

Thanks,
-Aleksey