Port and integrate the irregexp engine from V8

tests/language/regex/util.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.
+
+// Utility functions to easy porting of V8 tests.
+
+import "package:expect/expect.dart";
+
+void assertEquals(actual, expected, [message]) =>
+    Expect.equals(actual, expected, message);
+void assertTrue(actual, [message]) => Expect.isTrue(actual, message);
+void assertFalse(actual, [message]) => Expect.isFalse(actual, message);
+void assertThrows(fn, [testid]) => Expect.throws(fn);
+void assertNull(actual, [testid]) => Expect.isNull(actual);
+
+void assertToStringEquals(str, match, testid) {
+  var actual = [];
+  for (int i = 0; i <= match.groupCount; i++) {
+    actual.add(match.group(i));
+  }
+
+  Expect.equals(str,
+                actual.map((s) => (s == null) ? "" : s).join(","),
+                "Test $testid failed");
+}
+
+void shouldBeTrue(actual) => Expect.isTrue(actual);
+void shouldBeFalse(actual) => Expect.isFalse(actual);
+void shouldBeNull(actual) => Expect.isNull(actual);
+
+void shouldBe(actual, expected, [message]) {
+  if (expected == null) {
+    Expect.isNull(actual);
+  } else {
+    Expect.equals(expected.length, actual.groupCount + 1);
+    for (int i = 0; i <= actual.groupCount; i++) {
+      Expect.equals(expected[i], actual.group(i));
+    }
+  }
+}
+
+Match firstMatch(String str, RegExp pattern) => pattern.firstMatch(str);
+List<String> allStringMatches(String str, RegExp pattern) =>
+    pattern.allMatches(str).map((Match m) => m.group(0)).toList();
+
+void description(str) { }