Port and integrate the irregexp engine from V8

tests/language/regex/ecma-regex-examples_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 page tests the regex examples from the ECMA-262 specification."
+  );
+
+  var regex01 = new RegExp(r"a|ab");
+  shouldBe(regex01.firstMatch("abc"), ["a"]);
+
+  var regex02 = new RegExp(r"((a)|(ab))((c)|(bc))");
+  shouldBe(regex02.firstMatch("abc"), ["abc", "a", "a", null, "bc", null, "bc"]);
+
+  var regex03 = new RegExp(r"a[a-z]{2,4}");
+  shouldBe(regex03.firstMatch("abcdefghi"), ["abcde"]);
+
+  var regex04 = new RegExp(r"a[a-z]{2,4}?");
+  shouldBe(regex04.firstMatch("abcdefghi"), ["abc"]);
+
+  var regex05 = new RegExp(r"(aa|aabaac|ba|b|c)*");
+  shouldBe(regex05.firstMatch("aabaac"), ["aaba", "ba"]);
+
+  var regex06 = new RegExp(r"^(a+)\1*,\1+$");
+  Expect.equals("aaaaaaaaaa,aaaaaaaaaaaaaaa".replaceAllMapped(regex06,(m) => m.group(1)), "aaaaa");
+
+  var regex07 = new RegExp(r"(z)((a+)?(b+)?(c))*");
+  shouldBe(regex07.firstMatch("zaacbbbcac"), ["zaacbbbcac", "z", "ac", "a", null, "c"]);
+
+  var regex08 = new RegExp(r"(a*)*");
+  shouldBe(regex08.firstMatch("b"), ["", null]);
+
+  var regex09 = new RegExp(r"(a*)b\1+");
+  shouldBe(regex09.firstMatch("baaaac"), ["b", ""]);
+
+  var regex10 = new RegExp(r"(?=(a+))");
+  shouldBe(regex10.firstMatch("baaabac"), ["", "aaa"]);
+
+  var regex11 = new RegExp(r"(?=(a+))a*b\1");
+  shouldBe(regex11.firstMatch("baaabac"), ["aba", "a"]);
+
+  var regex12 = new RegExp(r"(.*?)a(?!(a+)b\2c)\2(.*)");
+  shouldBe(regex12.firstMatch("baaabaac"), ["baaabaac", "ba", null, "abaac"]);
+}