hg: shenandoah/jdk9/hotspot: [backport] Reinstate "Purge" block in final-mark stats

[ashipile at redhat.com]

Changeset: f0d541097cb8
Author:    shade
Date:      2017-07-20 21:50 +0200
URL:       http://hg.openjdk.java.net/shenandoah/jdk9/hotspot/rev/f0d541097cb8

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

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