Split dart:builtin into dart:builtin and dart:io.

tests/standalone/src/SocketCloseTest.dart

Index: tests/standalone/src/SocketCloseTest.dart
diff --git a/tests/standalone/src/SocketCloseTest.dart b/tests/standalone/src/SocketCloseTest.dart
index fb1df69a5213155e30337bd50dbb203b203a73c4..527d10de49b2e6c730d15762e726c5592e7b5388 100644
--- a/tests/standalone/src/SocketCloseTest.dart
+++ b/tests/standalone/src/SocketCloseTest.dart
@@ -1,14 +1,14 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, 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.
 //
 // Test socket close events.
 
+#import("dart:io");
 
 final SERVERSHUTDOWN = -1;
 final ITERATIONS = 10;
 
-
 class SocketClose {
 
   SocketClose.start(mode)