Port and integrate the irregexp engine from V8

tests/language/regex/extended-characters-match_test.dart

+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'util.dart';
+import 'package:expect/expect.dart';
+
+void main() {
+  description(
+  "This test checks regular expressions using extended (> 255) characters and character classes."
+  );
+
+  shouldBeNull((new RegExp("[\u0100-\u0101]")).firstMatch("a"));
+  shouldBeNull((new RegExp("[\u0100]")).firstMatch("a"));
+  shouldBeNull((new RegExp("\u0100")).firstMatch("a"));
+  assertEquals((new RegExp("[\u0061]")).firstMatch("a").group(0), "a");
+  assertEquals((new RegExp("[\u0100-\u0101a]")).firstMatch("a").group(0), "a");
+  assertEquals((new RegExp("[\u0100a]")).firstMatch("a").group(0), "a");
+  assertEquals((new RegExp("\u0061")).firstMatch("a").group(0), "a");
+  assertEquals((new RegExp("[a-\u0100]")).firstMatch("a").group(0), "a");
+  assertEquals((new RegExp("[\u0100]")).firstMatch("\u0100").group(0), "\u0100");
+  assertEquals((new RegExp("[\u0100-\u0101]")).firstMatch("\u0100").group(0), "\u0100");
+  assertEquals((new RegExp("\u0100")).firstMatch("\u0100").group(0), "\u0100");
+}