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

tests/standalone/io/process_broken_pipe_test.dart

Index: tests/standalone/io/process_broken_pipe_test.dart
diff --git a/tests/standalone/io/process_broken_pipe_test.dart b/tests/standalone/io/process_broken_pipe_test.dart
index 611f85036e0d407f750d61004525827c0ab31e38..8427cd539c121238aed426060c8b36d681cf1d91 100644
--- a/tests/standalone/io/process_broken_pipe_test.dart
+++ b/tests/standalone/io/process_broken_pipe_test.dart
@@ -4,9 +4,9 @@
 //
 // Process test program to test closed stdin from child process.
 
-#import('dart:io');
+import "dart:io";
 
-#source("process_test_util.dart");
+part "process_test_util.dart";
 
 main() {
   // Running dart without arguments makes it close right away.