Fix warnings_checker.dart handling of multitests

tests/lib/mirrors/generics_double_substitution_test.dart

Index: tests/lib/mirrors/generics_double_substitution_test.dart
diff --git a/tests/lib/mirrors/generics_double_substitution_test.dart b/tests/lib/mirrors/generics_double_substitution_test.dart
index 5eae4e6a1aace15fa392aea83445669dce45966b..ea3f5bc14d84087a9d63132250ec9a3e6dce35e0 100644
--- a/tests/lib/mirrors/generics_double_substitution_test.dart
+++ b/tests/lib/mirrors/generics_double_substitution_test.dart
@@ -29,5 +29,5 @@ main() {
   Expect.equals(aOfString, parameterType.parameters.single.type);
 
   ClassMirror typeArgOfSuperclass = cOfString.superclass.typeArguments.single;
-  Expect.equals(aOfString, typeArgOfSuperclass); // /// 01: ok
+  Expect.equals(aOfString, typeArgOfSuperclass); // //# 01: ok
 }