Fix warnings_checker.dart handling of multitests

tests/lib/mirrors/abstract_class_test.dart

Index: tests/lib/mirrors/abstract_class_test.dart
diff --git a/tests/lib/mirrors/abstract_class_test.dart b/tests/lib/mirrors/abstract_class_test.dart
index 00e108172dfd62cee2c395411510acc96021a2a8..30f3c278e94e84e425439d22eaeeef8c3f85c2ba 100644
--- a/tests/lib/mirrors/abstract_class_test.dart
+++ b/tests/lib/mirrors/abstract_class_test.dart
@@ -130,7 +130,7 @@ abstract class NamedMA = S with M;
 class SubNamedMA extends NamedMA {
   mixinFoo() {}
 }
-class ConcreteNamedMA = S with M; /// 00: static type warning
+class ConcreteNamedMA = S with M; //# 00: static type warning
 
 abstract class NamedMA2 = S with M2;
 class SubNamedMA2 extends NamedMA2 {
@@ -159,8 +159,8 @@ testNamedMixinApplication() {
   // Application is concrete.
   {
   // Mixin is abstract.
-  Expect.isFalse(reflectClass(ConcreteNamedMA).isAbstract); /// 00: ok
-  Expect.isFalse(reflectClass(ConcreteNamedMA).superclass.isAbstract); /// 00: ok
+  Expect.isFalse(reflectClass(ConcreteNamedMA).isAbstract); //# 00: ok
+  Expect.isFalse(reflectClass(ConcreteNamedMA).superclass.isAbstract); //# 00: ok
 
   // Mixin is concrete.
   Expect.isFalse(reflectClass(ConcreteNamedMA2).isAbstract);