Add new InternetAddress class with a static lookup function (including IPv6 results).

tests/standalone/io/http_keep_alive_test.dart

Index: tests/standalone/io/http_keep_alive_test.dart
diff --git a/tests/standalone/io/http_keep_alive_test.dart b/tests/standalone/io/http_keep_alive_test.dart
index c2160d3db075968ff7b27e79564742ed4a0d1d4a..b2d821a681e6ac934c46650c3a81a32fd3b9d135 100644
--- a/tests/standalone/io/http_keep_alive_test.dart
+++ b/tests/standalone/io/http_keep_alive_test.dart
@@ -12,7 +12,7 @@ import "dart:async";
 import "dart:io";
 
 Future getData(HttpClient client, int port, bool chunked, int length) {
-  return client.get("localhost", port, "/?chunked=$chunked&length=$length")
+  return client.get("127.0.0.1", port, "/?chunked=$chunked&length=$length")
       .then((request) => request.close())
       .then((response) {
         return response.fold(0, (bytes, data) => bytes + data.length)