Port and integrate the irregexp engine from V8

tests/language/regex/lastindex_test.dart

Index: tests/language/regex/lastindex_test.dart
diff --git a/tests/language/regex/lastindex_test.dart b/tests/language/regex/lastindex_test.dart
new file mode 100644
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+++ b/tests/language/regex/lastindex_test.dart
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+// 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() {
+  // 'Test for regression against "https://bugs.webkit.org/show_bug.cgi?id=5602"
+  // REGRESSION: RegExp("[^\\s$]+", "g") returns extra matches'
+
+  var re = new RegExp(r"[^\s$]+");
+  var accumulate = "";
+  var match;
+  for (var match in re.allMatches("  abcdefg"))
+    accumulate += match.group(0) + "; ";
+  assertEquals(accumulate, "abcdefg; ");
+
+  re = new RegExp(r"\d");
+  accumulate = "";
+  for (var match in re.allMatches("123456789"))
+    accumulate += match.group(0) + "; ";
+  assertEquals(accumulate, "1; 2; 3; 4; 5; 6; 7; 8; 9; ");
+}