[elements] update Dictionary in IncludesValue if own elements change

test/mjsunit/es7/regress/regress-634273.js

Index: test/mjsunit/es7/regress/regress-634273.js
diff --git a/test/mjsunit/es7/regress/regress-634273.js b/test/mjsunit/es7/regress/regress-634273.js
new file mode 100644
index 0000000000000000000000000000000000000000..7ee5b5a5fa8dfe51b01c40a07460c6cc4bd192fb
--- /dev/null
+++ b/test/mjsunit/es7/regress/regress-634273.js
@@ -0,0 +1,14 @@
+// Copyright 2016 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: --enable-slow-asserts
+
+array = new Array(undefined, undefined, undefined);
+Object.defineProperty(array, 0, {
+  get: function() {
+    array.push(undefined, undefined);
+  }
+});
+array[0x80000] = 1;
+result = array.includes(new WeakMap());