hg: shenandoah/jdk: Support VerifyBeforeGC and VerifyAfterGC VM options

[shade at redhat.com]

Changeset: 15b7de80abd3
Author:    shade
Date:      2018-10-20 23:44 +0200
URL:       http://hg.openjdk.java.net/shenandoah/jdk/rev/15b7de80abd3

Support VerifyBeforeGC and VerifyAfterGC VM options

! src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
! src/hotspot/share/gc/shenandoah/shenandoahMarkCompact.cpp
! src/hotspot/share/gc/shenandoah/shenandoahTraversalGC.cpp