Remove old #import, #source, and #library syntax from tests/standalone.

tests/standalone/io/test_extension_tester.dart

Index: tests/standalone/io/test_extension_tester.dart
diff --git a/tests/standalone/io/test_extension_tester.dart b/tests/standalone/io/test_extension_tester.dart
index 03991cda2e3ecde5696712eee3454db048e3d5e1..deacbaa5bbfdeb0f28688abf2fef899f61b2cf83 100644
--- a/tests/standalone/io/test_extension_tester.dart
+++ b/tests/standalone/io/test_extension_tester.dart
@@ -2,9 +2,9 @@
 // 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("test_extension_test");
+library test_extension_test;
 
-#import('test_extension.dart');
+import "test_extension.dart";
 
 main() {
   Expect.equals('cat 13', new Cat(13).toString(), 'new Cat(13).toString()');