Move isolate tests to lib/isolate.

tests/lib/async/deferred/deferred_library.dart

Index: tests/lib/async/deferred/deferred_library.dart
diff --git a/tests/lib/async/deferred/deferred_library.dart b/tests/lib/async/deferred/deferred_library.dart
deleted file mode 100644
index 186a11a19bbbb52c3578ed59b2ac3fd36db3a61b..0000000000000000000000000000000000000000
--- a/tests/lib/async/deferred/deferred_library.dart
+++ /dev/null
@@ -1,10 +0,0 @@
-// Copyright (c) 2013, 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.
-
-library deferred_api_library;
-
-foo(x) {
-  print('foo($x)');
-  return 42;
-}