[elements] limit TypedElementsAccessor::IncludesValue to backing store length

test/mjsunit/es7/regress/regress-634269.js

Index: test/mjsunit/es7/regress/regress-634269.js
diff --git a/test/intl/regexp-prepare.js b/test/mjsunit/es7/regress/regress-634269.js
similarity index 54%
copy from test/intl/regexp-prepare.js
copy to test/mjsunit/es7/regress/regress-634269.js
index dec84110ed02e30bba674538534a069f7d43d39d..3bd55eec414fa74856ce6bf21316e163e2b3c299 100644
--- a/test/intl/regexp-prepare.js
+++ b/test/mjsunit/es7/regress/regress-634269.js
@@ -2,4 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-/(\w)(\w)(\w)(\w)(\w)(\w)(\w)(\w)(\w)(\w)/.exec(">>>abcdefghij<<<");
+__v_1 = new Uint8Array();
+Object.defineProperty(__v_1.__proto__, 'length', {value: 42});
+Array.prototype.includes.call(new Uint8Array(), 2);