Gardening: Fix previous fix

tests/standalone/io/named_pipe_script_test.dart

Index: tests/standalone/io/named_pipe_script_test.dart
diff --git a/tests/standalone/io/named_pipe_script_test.dart b/tests/standalone/io/named_pipe_script_test.dart
index 8da51545283a27a260d9049d1c5f7d709adb268d..70599ed8a713fd8fbd9bb0a2e54ff8638cf9e176 100644
--- a/tests/standalone/io/named_pipe_script_test.dart
+++ b/tests/standalone/io/named_pipe_script_test.dart
@@ -14,6 +14,7 @@ main() async {
   // Reading a script from a named pipe is only supported on Linux and MacOS.
   if (!Platform.isLinux && !Platform.isMacOS) {
     print("This test is only supported on Linux and MacOS.");
+    asyncEnd();
     return;
   }
 
@@ -24,6 +25,7 @@ main() async {
   // test.
   if (!await (new File(stdinPipePath).exists())) {
     print("Couldn't find $stdinPipePath.");
+    asyncEnd();
     return;
   }