hg: shenandoah/jdk8u/hotspot: [backport] Reinstate "Purge" block in final-mark stats

[ashipile at redhat.com]

Changeset: aa09aa7952ba
Author:    shade
Date:      2017-07-20 21:51 +0200
URL:       http://hg.openjdk.java.net/shenandoah/jdk8u/hotspot/rev/aa09aa7952ba

[backport] Reinstate "Purge" block in final-mark stats

! src/share/vm/gc_implementation/shenandoah/shenandoahCollectorPolicy.hpp