Make generators non-constructable.

test/mjsunit/es6/object-literals-method.js

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --allow-natives-syntax
 
 
 (function TestBasics() {
   var object = {
     method() {
@@ skipping 221 matching lines @@
 (function TestGeneratorProto() {
   var object = {
     *method() {}
   };
 
   assertEquals(GeneratorFunction.prototype,
                Object.getPrototypeOf(object.method));
 })();
 
 
-(function TestGeneratorConstructable() {
+(function TestGeneratorNotConstructable() {
   var object = {
     *method() {
       yield 1;
     }
   };
 
-  var g = new object.method();
-  assertIteratorResult(1, false, g.next());
-  assertIteratorResult(undefined, true, g.next());
+  assertThrows(()=>new object.method());
 })();
 
 
 (function TestGeneratorName() {
   var object = {
     *method() {},
     *1() {},
     *2.0() {}
   };
   var f = object.method;
@@ skipping 43 matching lines @@
   var p = {};
   var object = {
     __proto__() {
       return 1;
     },
     __proto__: p
   };
   assertEquals(p, Object.getPrototypeOf(object));
   assertEquals(1, object.__proto__());
 })();