Do not call setters of read-only accessors.

test/mjsunit/readonly-accessor.js

Index: test/mjsunit/readonly-accessor.js
diff --git a/test/mjsunit/regress/regress-crbug-351262.js b/test/mjsunit/readonly-accessor.js
similarity index 71%
copy from test/mjsunit/regress/regress-crbug-351262.js
copy to test/mjsunit/readonly-accessor.js
index a2f4eadc0de5c2bd7d27f6e78ff9940fce7b0f85..5a73525fea60d67074d81e392d08d8448f8ae39d 100644
--- a/test/mjsunit/regress/regress-crbug-351262.js
+++ b/test/mjsunit/readonly-accessor.js
@@ -2,5 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-for (var x in this) {};
-JSON.stringify(this);
+var foo = {};
+foo.__proto__ = new String("bar");
+foo.length = 20;