Fix warnings_checker.dart handling of multitests

tests/language/issue18628_2_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.
 
 // This test checks for a regression found in Dart Editor: the
 // analyzer was treating [Type] as more specific than any type
 // variable (generic parameter).
 //
 // https://code.google.com/p/dart/issues/detail?id=18628
 
 class X<T extends Type> {}
 
 // This line is supposed to cause the warning; the other lines are
 // marked because they don't make sense when [Y] is not defined.
-class Y<U> extends X<U> {} /// 01: static type warning
+class Y<U> extends X<U> {} //# 01: static type warning
 
 main() {
-  X<Type> x = new X<Type>(); /// 01: static type warning
-  Y<Type> y = new Y<Type>(); /// 01: static type warning
+  X<Type> x = new X<Type>(); //# 01: static type warning
+  Y<Type> y = new Y<Type>(); //# 01: static type warning
 }