Add one more test for configurable imports.

tests/language/config_import_corelib_io.dart

Index: tests/language/config_import_corelib_io.dart
diff --git a/tests/language/config_import_corelib_io.dart b/tests/language/config_import_corelib_io.dart
new file mode 100644
index 0000000000000000000000000000000000000000..d5b594ad32b8d09614db711de745423524db1ffe
--- /dev/null
+++ b/tests/language/config_import_corelib_io.dart
@@ -0,0 +1,14 @@
+// Copyright (c) 2015, 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";
+
+class Classy {
+  String get name => "classy io";
+  String ioSpecific() => "classy io";
+}
+
+bool general() => true;
+bool ioSpecific() => true;
+final String name = "io";