Fix warnings_checker.dart handling of multitests

tests/language_strong/super_setter_test.dart

Index: tests/language_strong/super_setter_test.dart
diff --git a/tests/language_strong/super_setter_test.dart b/tests/language_strong/super_setter_test.dart
index 4a9792f3f9921e5d3ab2656a8909be297c20a2a1..f5be4008815eb63c66fffe82ac5e4f0d673616bb 100644
--- a/tests/language_strong/super_setter_test.dart
+++ b/tests/language_strong/super_setter_test.dart
@@ -10,7 +10,7 @@ class Base {
   String value_;
 
   String get value { return value_; }
-  String set value(String newValue) { /// static warning
+  String set value(String newValue) { //# static warning
     value_ = 'Base:$newValue';
   }
 }
@@ -19,7 +19,7 @@ class Base {
 class Derived extends Base {
   Derived() : super() {}
 
-  String set value(String newValue) { /// static warning
+  String set value(String newValue) { //# static warning
     super.value = 'Derived:$newValue';
   }
   String get value { return super.value; }