[strong] Implement strong property access semantics

test/mjsunit/strong/functions.js

 // Copyright 2015 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: --strong-mode
 
 'use strong';
 
 function f() {}
 function* g() {}
@@ skipping 29 matching lines @@
 (function NoCallee() {
   assertFalse("callee" in f);
   assertFalse("callee" in g);
   assertThrows(function(){ f.callee = 0 }, TypeError);
   assertThrows(function(){ g.callee = 0 }, TypeError);
 })();
 
 (function LexicalBindings(global) {
   assertEquals('function', typeof f);
   assertEquals('function', typeof g);
-  assertEquals(undefined, global.f);
-  assertEquals(undefined, global.g);
+  assertFalse(global.hasOwnProperty("f"));
+  assertFalse(global.hasOwnProperty("g"));
 })(this);
 
 (function ImmutableBindings() {
   function f2() {}
   function* g2() {}
   assertThrows(function(){ f = 0 }, TypeError);
   assertThrows(function(){ g = 0 }, TypeError);
   assertThrows(function(){ f2 = 0 }, TypeError);
   assertThrows(function(){ g2 = 0 }, TypeError);
   assertEquals('function', typeof f);
@@ skipping 16 matching lines @@
   assertFalse(g.hasOwnProperty("prototype"));
   assertThrows(function(){ f.prototype = 0 }, TypeError);
   assertThrows(function(){ g.prototype = 0 }, TypeError);
   assertThrows(function(){ f.prototype.a = 0 }, TypeError);
 })();
 
 (function NonConstructor() {
   assertThrows(function(){ new f }, TypeError);
   assertThrows(function(){ new g }, TypeError);
 })();