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

tests/standalone/src/StringStreamTest.dart

Index: tests/standalone/src/StringStreamTest.dart
diff --git a/tests/standalone/src/StringStreamTest.dart b/tests/standalone/src/StringStreamTest.dart
index 667b9b2954665abbadc416bcb9fdb81efea35eb8..13d88bb9a93e5ec5c1d0b4a50bd4336a59069c2c 100644
--- a/tests/standalone/src/StringStreamTest.dart
+++ b/tests/standalone/src/StringStreamTest.dart
@@ -1,7 +1,9 @@
-// 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.
 
+#import("dart:io");
+
 void testUtf8() {
   List<int> data = [0x01,
                     0x7f,