Port and integrate the irregexp engine from V8

tests/language/regex/capture_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() {
+  // Tests from http://blog.stevenlevithan.com/archives/npcg-javascript
+
+  assertEquals(true, new RegExp(r"(x)?\1y").hasMatch("y"));
+  shouldBe(new RegExp(r"(x)?\1y").firstMatch("y"), ["y", null]);
+  shouldBe(new RegExp(r"(x)?y").firstMatch("y"), ["y", null]);
+  shouldBe(firstMatch("y", new RegExp(r"(x)?\1y")), ["y", null]);
+  shouldBe(firstMatch("y", new RegExp(r"(x)?y")), ["y", null]);
+  shouldBe(firstMatch("y", new RegExp(r"(x)?\1y")), ["y", null]);
+  Expect.listEquals(["", ""], "y".split(new RegExp(r"(x)?\1y")));
+  Expect.listEquals(["", ""], "y".split(new RegExp(r"(x)?y")));
+  assertEquals(0, "y".indexOf(new RegExp(r"(x)?\1y")));
+  assertEquals("z", "y".replaceAll(new RegExp(r"(x)?\1y"), "z"));
+
+  // See https://bugzilla.mozilla.org/show_bug.cgi?id=476146
+  shouldBe(new RegExp(r"^(b+|a){1,2}?bc").firstMatch("bbc"), ["bbc", "b"]);
+  shouldBe(new RegExp(r"((\3|b)\2(a)){2,}").firstMatch("bbaababbabaaaaabbaaaabba"),
+      ["bbaa", "a", "", "a"]);
+
+  // From crbug.com/128821 - don't hang:
+  firstMatch("", new RegExp(r"((a|i|A|I|u|o|U|O)(s|c|b|c|d|f|g|h|j|k|l|m|n|p|q|r|s|t|v|w|x|y|z|B|C|D|F|G|H|J|K|L|M|N|P|Q|R|S|T|V|W|X|Y|Z)*) de\/da([.,!?\s]|$)"));
+}