[intl] Remove redundant type checking system

test/mjsunit/regress/regress-4962.js

Index: test/mjsunit/regress/regress-4962.js
diff --git a/test/mjsunit/regress/regress-4962.js b/test/mjsunit/regress/regress-4962.js
new file mode 100644
index 0000000000000000000000000000000000000000..f8c96e336e829905e257749c9268e50b81fd878a
--- /dev/null
+++ b/test/mjsunit/regress/regress-4962.js
@@ -0,0 +1,11 @@
+// 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.
+
+if (this.Intl) {
+  assertInstanceof(Intl.NumberFormat.call(new Proxy({},{})), Intl.NumberFormat);
+  assertThrows(() =>
+               Intl.DateTimeFormat.prototype.formatToParts.call(
+                   new Proxy({}, {})),
+               TypeError);
+}