Fix warnings_checker.dart handling of multitests

tests/language/deferred_inheritance_constraints_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import "package:expect/expect.dart";
 import "deferred_inheritance_constraints_lib.dart" deferred as lib;
 
 class Foo {}
 class Foo2 extends D {}
  
 class A extends 
-  lib. /// extends: compile-time error
+  lib. //# extends: compile-time error
   Foo {} 
 class B implements 
-  lib. /// implements: compile-time error
+  lib. //# implements: compile-time error
   Foo {}
 class C1 {}
 class C = C1 with 
-  lib. /// mixin: compile-time error
+  lib. //# mixin: compile-time error
   Foo; 
 
 class D { 
   D() ;
   factory D.factory() = 
-    lib. /// redirecting_constructor: static type warning
+    lib. //# redirecting_constructor: static type warning
     Foo2;
 }
 
 void main() {
   new A();
   new B();
   new C();
-  Expect.throws(() { /// redirecting_constructor: continued
+  Expect.throws(() { //# redirecting_constructor: continued
     new D.factory();
-  }); /// redirecting_constructor: continued
+  }); //# redirecting_constructor: continued
 }