Add regression test to assert buffer overrun

Bug: v8:7770
Change-Id: I649dd1fb52c1598281e7f70cce74b1798504640a
Reviewed-on: https://chromium-review.googlesource.com/c/1436598
Commit-Queue: Frank Tang <ftang@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59147}

test/intl/intl.status

@@ -46,6 +46,9 @@
 
   # Unable to change locale on Windows:
   'default_locale': [SKIP],
+
+  # Unable to change locale and TZ on Windows:
+  'regress-7770': [SKIP],
 }],  # system == windows'
 
 ['system == android', {

test/intl/regress-7770.js

+// Copyright 2019 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.
+
+// Environment Variables: TZ=Indian/Kerguelen LANG=uk
+assertEquals(
+  "Fri Feb 01 2019 00:00:00 GMT+0500 (за часом на Французьких Південних і Антарктичних територіях)",
+  new Date(2019, 1,1).toString());