Remove support for Object.observe

test/mjsunit/migrations.js

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-ayle license that can be
 // found in the LICENSE file.
 
-// Flags: --harmony-object-observe
 // Flags: --allow-natives-syntax --track-fields --expose-gc
 
 var global = Function('return this')();
 var verbose = 0;
 
 function test(ctor_desc, use_desc, migr_desc) {
   var n = 5;
   var objects = [];
   var results = [];
 
@@ skipping 252 matching lines @@
     name: "set property callback",
     migr: function(o, i) {
       Object.defineProperty(o, "a", {
         get: function() { return 1.5 + i; },
         set: function(value) {},
         configurable: true,
       });
     },
   },
   {
-    name: "observe",
-    migr: function(o, i) { Object.observe(o, function(){}); },
-  },
-  {
     name: "seal",
     migr: function(o, i) { Object.seal(o); },
   },
   { // Must be the last in the sequence, because after the global object freeze
     // the other modifications does not make sence.
     name: "freeze",
     migr: function(o, i) { Object.freeze(o); },
   },
 ];
 
 
 
 migrations.forEach(function(migr) {
   uses.forEach(function(use) {
     ctors.forEach(function(ctor) {
       test(ctor, use, migr);
     });
   });
 });