Issue #1094: minor improvement for Utils/test_mode_check
diff --git a/Utils/test_mode_check.dart b/Utils/test_mode_check.dart
index a4ce513..9861bb2 100644
--- a/Utils/test_mode_check.dart
+++ b/Utils/test_mode_check.dart
@@ -5,9 +5,9 @@
 library test_mode_check;
 import "dart:io";
 
-typedef check = bool Function(String);
+typedef CheckExecutable = bool Function(String s);
 
-bool checkMode(check ret) {
+bool checkMode(CheckExecutable ret) {
   var parts = Uri.file(Platform.resolvedExecutable).pathSegments;
   String basename =  parts[parts.length - 1];
   var pos = basename.lastIndexOf('.');