Fix warnings_checker.dart handling of multitests

tests/language/import_self_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.
 //
 // Check that private names cannot be imported even if the library imports
 // itself.
 
 library import_self;
 
 import "package:expect/expect.dart";
 
 // Eliminate the import of the unmodified file or else the analyzer
 // will generate the static warning in the import_self_test_none case.
-import "import_self_test.dart" as p; // /// 01: continued
+import "import_self_test.dart" as p; // //# 01: continued
 
 var _x = "The quick brown fox jumps over the dazy log";
 
 main() {
   var t = "Falsches Üben von Xylophonmusik quält jeden größeren Zwerg";
 
   // Check that referencing p._x causes a warning from the analyzer,
   // and the runtime fails to resolve p._x, even though it refers to
   // top level variable _x of this file.
-  Expect.throws(() { t = p._x; }, // /// 01: static type warning
-                (e) => e is NoSuchMethodError); // /// 01: continued
+  Expect.throws(() { t = p._x; }, // //# 01: static type warning
+                (e) => e is NoSuchMethodError); // //# 01: continued
 
   Expect.isTrue(t.endsWith("Zwerg"));
 }