VectorICs: Bugfix in KeyedStore dispatcher.

test/mjsunit/regress/regress-4495.js

Index: test/mjsunit/regress/regress-4495.js
diff --git a/test/mjsunit/regress/regress-4495.js b/test/mjsunit/regress/regress-4495.js
new file mode 100644
index 0000000000000000000000000000000000000000..2af5bc2445c17dc2160dabbf7f53c717bfc6f9dd
--- /dev/null
+++ b/test/mjsunit/regress/regress-4495.js
@@ -0,0 +1,11 @@
+// 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.
+
+function foo(a, s) { a[s] = 35; }
+var x = { bilbo: 3 };
+var y = { frodo: 3, bilbo: 'hi' };
+foo(x, "bilbo");
+foo(x, "bilbo");
+// Without the fix for 4495, this will crash on ia32:
+foo(y, "bilbo");