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

tests/standalone/io/http_proxy_test.dart

Index: tests/standalone/io/http_proxy_test.dart
diff --git a/tests/standalone/io/http_proxy_test.dart b/tests/standalone/io/http_proxy_test.dart
index 5ab12b1feda40dbee8ef2bf0e60846d20e2e663a..8232769338e2f6a7d567067bc60f881eeaff8198 100644
--- a/tests/standalone/io/http_proxy_test.dart
+++ b/tests/standalone/io/http_proxy_test.dart
@@ -2,8 +2,8 @@
 // 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");
-#import("dart:uri");
+import "dart:io";
+import "dart:uri";
 
 class Server {
   HttpServer server;