hg: shenandoah/jdk10: Verifier should check klass pointers before attempting to reach for object size

[ashipile at redhat.com]

Changeset: 90f120de8a35
Author:    shade
Date:      2017-12-14 12:02 +0100
URL:       http://hg.openjdk.java.net/shenandoah/jdk10/rev/90f120de8a35

Verifier should check klass pointers before attempting to reach for object size

! src/hotspot/share/gc/shenandoah/shenandoahVerifier.cpp