ignore trailing whitespace in polymer transform test

pkg/polymer/test/transform/all_phases_test.dart

Index: pkg/polymer/test/transform/all_phases_test.dart
diff --git a/pkg/polymer/test/transform/all_phases_test.dart b/pkg/polymer/test/transform/all_phases_test.dart
index 81de2f95340549720aa4f36130d7cbf0e45dc500..743b199edc272b0042520133ec90e68d5fbfdb2b 100644
--- a/pkg/polymer/test/transform/all_phases_test.dart
+++ b/pkg/polymer/test/transform/all_phases_test.dart
@@ -211,7 +211,7 @@ class $className extends ChangeNotifierBase {
   set $fieldName(int value) {
     __\$$fieldName = notifyPropertyChange(const Symbol('$fieldName'), __\$$fieldName, value);
   }
-  
+
   $className($fieldName) : __\$$fieldName = $fieldName;
 }
 ''';