Make generators non-constructable.

test/mjsunit/es6/generators-objects.js

Index: test/mjsunit/es6/generators-objects.js
diff --git a/test/mjsunit/es6/generators-objects.js b/test/mjsunit/es6/generators-objects.js
index 9390776761607df9c963479e1c601e61c331fff9..f304738841883bdae408d76b3efb4d5e2f71f27e 100644
--- a/test/mjsunit/es6/generators-objects.js
+++ b/test/mjsunit/es6/generators-objects.js
@@ -59,18 +59,12 @@ function TestGeneratorObject() {
   assertEquals("[object Generator]", String(iter));
   assertEquals([], Object.getOwnPropertyNames(iter));
   assertTrue(iter !== g());
-
-  // g() is the same as new g().
-  iter = new g();
-  assertSame(g.prototype, Object.getPrototypeOf(iter));
-  assertTrue(iter instanceof g);
-  assertEquals("Generator", %_ClassOf(iter));
-  assertEquals("[object Generator]", String(iter));
   assertEquals("[object Generator]", Object.prototype.toString.call(iter));
   var gf = iter.__proto__.constructor;
   assertEquals("[object GeneratorFunction]", Object.prototype.toString.call(gf));
-  assertEquals([], Object.getOwnPropertyNames(iter));
-  assertTrue(iter !== new g());
+
+  // generators are not constructable.
+  assertThrows(()=>new g());
 }
 TestGeneratorObject();