Port and integrate the irregexp engine from V8

tests/language/regex/alternative-length-miscalculation_test.dart

Index: tests/language/regex/alternative-length-miscalculation_test.dart
diff --git a/tests/language/deferred_closurize_load_library_test.dart b/tests/language/regex/alternative-length-miscalculation_test.dart
similarity index 50%
copy from tests/language/deferred_closurize_load_library_test.dart
copy to tests/language/regex/alternative-length-miscalculation_test.dart
index 6c90cb6147fb142b52d7c84cf8bb9cb97385a179..4c532f9b2c7712f8bd29b21f538015ae8faf3107 100644
--- a/tests/language/deferred_closurize_load_library_test.dart
+++ b/tests/language/regex/alternative-length-miscalculation_test.dart
@@ -2,16 +2,17 @@
 // 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';
-import 'package:async_helper/async_helper.dart';
-
-import "deferred_closurize_load_library_lib.dart" deferred as lib;
 
 void main() {
-  var x = lib.loadLibrary;
-  asyncStart();
-  x().then((_) {
-    Expect.isTrue(lib.trueVar);
-    asyncEnd();
-  });
+  description(
+  "This page tests for length miscalculations in regular expression processing."
+  );
+
+  var re = new RegExp(r"b|[^b]");
+  assertEquals('a'.indexOf(re, 1), -1);
+
+  var re2 = new RegExp(r"[^a]|ab");
+  shouldBeFalse(re2.hasMatch(''));
 }