RFR (XS): JDK-8058534: Remove HeapRegion::_orig_end

[Joseph Provino]

Hi all,

Can I have reviews for the following small change that removes the
_orig_end member from the HeapRegion class. The information this member
stores can be easily recalculated on the fly, so it is just a waste of a
few bytes.

CR:https://bugs.openjdk.java.net/browse/JDK-8058534

Webrev:http://cr.openjdk.java.net/~jprovino/8058534/webrev.00/

Testing: jprt

I also need a sponsor to commit the changes.  Thomas Schatzl has agreed 
to do that.

Thanks.

joe