Fix warnings_checker.dart handling of multitests

tests/language_strong/mixin_illegal_syntax_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 S { }
 class G<T> { }
 class M { }
 
 typedef T0 = abstract S with M;
 abstract class T0A = S with M;
-class T1 = final S with M; //    /// 01: compile-time error
-class T2 = var S with M; //      /// 02: compile-time error
-class T3 = const S with M; //    /// 03: compile-time error
-class T4 = static S with M; //   /// 04: compile-time error
-class T5 = external S with M; // /// 05: compile-time error
+class T1 = final S with M; //    //# 01: compile-time error
+class T2 = var S with M; //      //# 02: compile-time error
+class T3 = const S with M; //    //# 03: compile-time error
+class T4 = static S with M; //   //# 04: compile-time error
+class T5 = external S with M; // //# 05: compile-time error
 class T6 = G<int> with M;
 class T7 = G<Map<String,int>> with M;
 
-class C0 extends abstract S with M { } // /// 06: compile-time error
-class C1 extends final S with M { } //    /// 07: compile-time error
-class C2 extends var S with M { } //      /// 08: compile-time error
-class C3 extends const S with M { } //    /// 09: compile-time error
-class C4 extends static S with M { } //   /// 10: compile-time error
-class C5 extends external S with M { } // /// 11: compile-time error
+class C0 extends abstract S with M { } // //# 06: compile-time error
+class C1 extends final S with M { } //    //# 07: compile-time error
+class C2 extends var S with M { } //      //# 08: compile-time error
+class C3 extends const S with M { } //    //# 09: compile-time error
+class C4 extends static S with M { } //   //# 10: compile-time error
+class C5 extends external S with M { } // //# 11: compile-time error
 class C6 extends G<int> with M { }
 class C7 extends G<Map<String,int>> with M { }
 
 class D0 extends S with M
-    implements M // /// 12: compile-time error
+    implements M // //# 12: compile-time error
     implements M { }
 
 class D1 extends T0 { }
 
-class X = S; //  /// 14: compile-time error
+class X = S; //  //# 14: compile-time error
 
 main() {
-  new T0(); // /// 13: static type warning, runtime error
-  new T0A(); // /// 13: static type warning, runtime error
-  new T1(); // /// 01: continued
-  new T2(); // /// 02: continued
-  new T3(); // /// 03: continued
-  new T4(); // /// 04: continued
-  new T5(); // /// 05: continued
+  new T0(); // //# 13: static type warning, runtime error
+  new T0A(); // //# 13: static type warning, runtime error
+  new T1(); // //# 01: continued
+  new T2(); // //# 02: continued
+  new T3(); // //# 03: continued
+  new T4(); // //# 04: continued
+  new T5(); // //# 05: continued
   new T6();
   new T7();
 
-  new C0(); // /// 06: continued
-  new C1(); // /// 07: continued
-  new C2(); // /// 08: continued
-  new C3(); // /// 09: continued
-  new C4(); // /// 10: continued
-  new C5(); // /// 11: continued
+  new C0(); // //# 06: continued
+  new C1(); // //# 07: continued
+  new C2(); // //# 08: continued
+  new C3(); // //# 09: continued
+  new C4(); // //# 10: continued
+  new C5(); // //# 11: continued
   new C6();
   new C7();
 
-  new D0(); // /// 12: continued
+  new D0(); // //# 12: continued
   new D1();
-  new X(); //  /// 14: continued
+  new X(); //  //# 14: continued
 }