Fixed 6484957 G1: parallel concurrent refinement Fixed 6826318 G1: remove traversal-based refinement code Removed traversal-based refinement code as it's no longer used. Made the concurrent refinement (queue-based) parallel. Webrev: http://cr.openjdk.java.net/~iveresov/6484957/webrev.00 Testing: specjbb2005, jprt