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

tests/standalone/io/process_environment_test.dart

Index: tests/standalone/io/process_environment_test.dart
diff --git a/tests/standalone/io/process_environment_test.dart b/tests/standalone/io/process_environment_test.dart
index df635ec8fb7b8a6c754877d2e3a58ba1b1fe1b69..e4aaf842955a7d3110e5299f3d4cf8cf55426e92 100644
--- a/tests/standalone/io/process_environment_test.dart
+++ b/tests/standalone/io/process_environment_test.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.
 
-#import('dart:io');
-#import('dart:isolate');
-#source('process_test_util.dart');
+import "dart:io";
+import "dart:isolate";
+part "process_test_util.dart";
 
 runEnvironmentProcess(Map environment, name, callback) {
   var dartExecutable = new Options().executable;