Fix warnings_checker.dart handling of multitests

tests/language/illegal_initializer_test.dart

 // Copyright (c) 2013, 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.
 
 class A {
   A();
   A.foo();
 }
 
 class B extends A {
   B.c1() : super.foo
-  /* // /// 01: compile-time error
+  /* // //# 01: compile-time error
   ()
-  */ // /// 01: continued
+  */ // //# 01: continued
   ;
 
   B.foo();
   B.c2() : this.foo
-  /* // /// 02: compile-time error
+  /* // //# 02: compile-time error
   ()
-  */ // /// 02: continued
+  */ // //# 02: continued
   ;
 
   B.c3() : super
-  /* // /// 03: compile-time error
+  /* // //# 03: compile-time error
   ()
-  */ // /// 03: continued
+  */ // //# 03: continued
   ;
 
   B();
   B.c4() : this
-  /* // /// 04: compile-time error
+  /* // //# 04: compile-time error
   ()
-  */ // /// 04: continued
+  */ // //# 04: continued
   ;
 }
 
 main() {
   new B.c1();
   new B.c2();
   new B.c3();
   new B.c4();
 }