docs: @Override
      public boolean hasInstance(Scriptable instance)
      {
          Object protoProp = ScriptableObject.getProperty(this, "prototype");
          if (protoProp instanceof Scriptable) {
              return ScriptRuntime.jsDelegatesTo(instance, (Scriptable)protoProp);
          }
          throw ScriptRuntime.typeError1("msg.instanceof.bad.prototype",
                                         getFunctionName());
      }