Synchronize with r15594.

test/intl/date-format/protected-icu-internals.js

Index: test/intl/date-format/protected-icu-internals.js
diff --git a/test/mjsunit/regress/regress-237617.js b/test/intl/date-format/protected-icu-internals.js
similarity index 72%
copy from test/mjsunit/regress/regress-237617.js
copy to test/intl/date-format/protected-icu-internals.js
index dabf828ae8bbfa3223e56664a97780098e6c5e3e..140f4b594d8a7d4d6f35734956d6d8e20ff9c06d 100644
--- a/test/mjsunit/regress/regress-237617.js
+++ b/test/intl/date-format/protected-icu-internals.js
@@ -25,19 +25,25 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-"use strict"
+// Internal object we got from native code should not be writable,
+// configurable or enumerable. One can still change its public properties, but
+// we don't use them to do actual work.
 
-function f() {
-  throw new Error("test stack");
-}
+var format = new Intl.DateTimeFormat([]);
+
+// Direct write should fail.
+format.formatter = {'zzz':'some random object'};
 
-var error_stack = "";
+assertFalse(format.formatter.hasOwnProperty('zzz'));
+
+// Try redefining the property.
+var didThrow = false;
 try {
-  f.call(null);
-} catch (e) {
-  error_stack = e.stack;
+  Object.defineProperty(format, 'formatter', {value: undefined});
+} catch(e) {
+  didThrow = true;
 }
+assertTrue(didThrow);
 
-assertTrue(error_stack.indexOf("test stack") > 0);
-assertTrue(error_stack.indexOf("illegal") < 0);
-
+// Try deleting the property.
+assertFalse(delete format.formatter);