Following the discussion in JDK-8259609, we should update _max_classes in node type system. it should be the last class of node in the system.
Currently, it points to the second to last.

enum NodeClasses {
...
    DEFINE_CLASS_ID(Move, Node, 17)
    DEFINE_CLASS_ID(LShift, Node, 18)

    _max_classes = ClassMask_Move
}