6975210: java.lang.VerifyError in some of JCK tests

Summary: Naked oop in verificationType::is_reference_assignable_from()
Reviewed-by: never, kvn, coleenp

src/share/vm/classfile/verificationType.cpp

@@ -54,10 +54,12 @@ bool VerificationType::is_reference_assignable_from(
       // any object or array is assignable to java.lang.Object
       return true;
     }
-    klassOop this_class = SystemDictionary::resolve_or_fail(
+    klassOop obj = SystemDictionary::resolve_or_fail(
         name_handle(), Handle(THREAD, context->class_loader()),
         Handle(THREAD, context->protection_domain()), true, CHECK_false);
-    if (this_class->klass_part()->is_interface()) {
+    KlassHandle this_class(THREAD, obj);
+
+    if (this_class->is_interface()) {
       // We treat interfaces as java.lang.Object, including
       // java.lang.Cloneable and java.io.Serializable
       return true;
@@ -65,7 +67,7 @@ bool VerificationType::is_reference_assignable_from(
       klassOop from_class = SystemDictionary::resolve_or_fail(
           from.name_handle(), Handle(THREAD, context->class_loader()),
           Handle(THREAD, context->protection_domain()), true, CHECK_false);
-      return instanceKlass::cast(from_class)->is_subclass_of(this_class);
+      return instanceKlass::cast(from_class)->is_subclass_of(this_class());
     }
   } else if (is_array() && from.is_array()) {
     VerificationType comp_this = get_component(CHECK_false);