Port and integrate the irregexp engine from V8

tests/language/regex/bol_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(
+  'Test for beginning of line (BOL or ^) matching</a>'
+  );
+
+  var s = "abc123def456xyzabc789abc999";
+  shouldBeNull(firstMatch(s, new RegExp(r"^notHere")));
+  shouldBe(firstMatch(s, new RegExp(r"^abc")), ["abc"]);
+  shouldBe(firstMatch(s, new RegExp(r"(^|X)abc")), ["abc",""]);
+  shouldBe(firstMatch(s, new RegExp(r"^longer|123")), ["123"]);
+  shouldBe(firstMatch(s, new RegExp(r"(^abc|c)123")), ["abc123","abc"]);
+  shouldBe(firstMatch(s, new RegExp(r"(c|^abc)123")), ["abc123","abc"]);
+  shouldBe(firstMatch(s, new RegExp(r"(^ab|abc)123")), ["abc123","abc"]);
+  shouldBe(firstMatch(s, new RegExp(r"(bc|^abc)([0-9]*)a")), ["bc789a","bc","789"]);
+  shouldBeNull(new RegExp(r"(?:(Y)X)|(X)").firstMatch("abc"));
+  shouldBeNull(new RegExp(r"(?:(?:^|Y)X)|(X)").firstMatch("abc"));
+  shouldBeNull(new RegExp(r"(?:(?:^|Y)X)|(X)").firstMatch("abcd"));
+  shouldBe(new RegExp(r"(?:(?:^|Y)X)|(X)").firstMatch("Xabcd"), ["X",null]);
+  shouldBe(new RegExp(r"(?:(?:^|Y)X)|(X)").firstMatch("aXbcd"), ["X","X"]);
+  shouldBe(new RegExp(r"(?:(?:^|Y)X)|(X)").firstMatch("abXcd"), ["X","X"]);
+  shouldBe(new RegExp(r"(?:(?:^|Y)X)|(X)").firstMatch("abcXd"), ["X","X"]);
+  shouldBe(new RegExp(r"(?:(?:^|Y)X)|(X)").firstMatch("abcdX"), ["X","X"]);
+  shouldBe(new RegExp(r"(?:(?:^|Y)X)|(X)").firstMatch("YXabcd"), ["YX",null]);
+  shouldBe(new RegExp(r"(?:(?:^|Y)X)|(X)").firstMatch("aYXbcd"), ["YX",null]);
+  shouldBe(new RegExp(r"(?:(?:^|Y)X)|(X)").firstMatch("abYXcd"), ["YX",null]);
+  shouldBe(new RegExp(r"(?:(?:^|Y)X)|(X)").firstMatch("abcYXd"), ["YX",null]);
+  shouldBe(new RegExp(r"(?:(?:^|Y)X)|(X)").firstMatch("abcdYX"), ["YX",null]);
+}