Review request: Clean up BarrierSet contructors and destructors

[Thomas Schatzl]

On Fri, 2015-01-23 at 16:53 -0500, Joseph Provino wrote:
> Can I get reviews for this small change?
> 
> I also need a sponsor to push the change.
> 
> Webrev and bug report are here:
> 
> http://cr.openjdk.java.net/~jprovino/8064947/webrev.01
> 
> https://bugs.openjdk.java.net/browse/JDK-8064947

The change looks good.

Thanks,
Thomas