Fix warnings_checker.dart handling of multitests

tests/language/generic_field_mixin6_test.dart

Index: tests/language/generic_field_mixin6_test.dart
diff --git a/tests/language/generic_field_mixin6_test.dart b/tests/language/generic_field_mixin6_test.dart
index 6bdb624d90c0345131ca64d42244751c5f6538d1..664246a9042cd00aca6c660999a3eb8e8ca38b53 100644
--- a/tests/language/generic_field_mixin6_test.dart
+++ b/tests/language/generic_field_mixin6_test.dart
@@ -7,7 +7,7 @@
 import 'package:expect/expect.dart';
 
 class M<T> {
-  T field = 0; /// 01: static type warning
+  T field = 0; //# 01: static type warning
 }
 class A<U> {}
 class C1<V> = Object with M<V>;
@@ -15,12 +15,12 @@ class C2 = Object with M<int>;
 class C3 = Object with M<String>;
 
 main() {
-  checkNoDynamicTypeError(() => new C1<int>()); // /// 01: continued
-  checkDynamicTypeError(() => new C1<String>()); /// 01: continued
+  checkNoDynamicTypeError(() => new C1<int>()); // //# 01: continued
+  checkDynamicTypeError(() => new C1<String>()); //# 01: continued
 
-  checkNoDynamicTypeError(() => new C2()); //      /// 01: continued
+  checkNoDynamicTypeError(() => new C2()); //      //# 01: continued
 
-  checkDynamicTypeError(() => new C3()); //        /// 01: continued
+  checkDynamicTypeError(() => new C3()); //        //# 01: continued
 }
 
 /// Returns `true` if the program is running in checked mode.