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

tests/standalone/io/file_output_stream_test.dart

Index: tests/standalone/io/file_output_stream_test.dart
diff --git a/tests/standalone/io/file_output_stream_test.dart b/tests/standalone/io/file_output_stream_test.dart
index 412ea5c04304d7bd0bacc7000dd936deaa591b57..88b314cb1fd3f0d5388986e7f7c2d11c54114703 100644
--- a/tests/standalone/io/file_output_stream_test.dart
+++ b/tests/standalone/io/file_output_stream_test.dart
@@ -3,8 +3,8 @@
 // BSD-style license that can be found in the LICENSE file.
 // Testing file input stream, VM-only, standalone test.
 
-#import("dart:io");
-#import("dart:isolate");
+import "dart:io";
+import "dart:isolate";
 
 void testOpenOutputStreamSync() {
   Directory tempDirectory = new Directory('').createTempSync();