Fix warnings_checker.dart handling of multitests

tests/language_strong/generic_methods_overriding_test.dart

 // Copyright (c) 2017, 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.
 
 // Test that generic methods can be overloaded (a) with widened type bounds, and
 // (b) using the bound as the type of the parameter in the overloaded method.
 
 library generic_methods_overriding_test;
 
 import "package:expect/expect.dart";
 
 class X {}
 
 class Y extends X {}
 
 class Z extends Y {}
 
 class C {
   String fun<T extends Y>(T t) => "C";
 }
 
 class D extends C {
-  String fun<T extends X>(T t) => "D"; /// 01: compile-time error
-  String fun<T extends Y>(T t) => "D"; /// 02: ok
+  String fun<T extends X>(T t) => "D"; //# 01: compile-time error
+  String fun<T extends Y>(T t) => "D"; //# 02: ok
 }
 
 class E extends C {
-  String fun<T>(Y y) => "E"; /// 03: compile-time error
-  String fun<T extends Y>(Y y) => "E"; /// 04: ok
+  String fun<T>(Y y) => "E"; //# 03: compile-time error
+  String fun<T extends Y>(Y y) => "E"; //# 04: ok
 }
 
 class F extends C {
   String foobar(Z z) {
     return "FZ";
   }
 
   String fun<T extends Y>(T t) {
     if (t is Z) {
-      return this.foobar(t as Z); /// 05: ok
-      return this.foobar(t); /// 06: ok
+      return this.foobar(t as Z); //# 05: ok
+      return this.foobar(t); //# 06: ok
     }
     return "FY";
   }
 }
 
 main() {
   Y y = new Y();
   Z z = new Z();
 
   C c = new C();
   D d = new D();
   E e = new E();
   F f = new F();
 
   Expect.equals(c.fun<Y>(y), "C");
-  Expect.equals(d.fun<Y>(y), "D"); /// 02: continued
-  Expect.equals(e.fun<Y>(y), "E"); /// 04: continued
-  Expect.equals(f.fun<Y>(y), "FY"); /// 05: continued
-  Expect.equals(f.fun<Z>(z), "FZ"); /// 05: continued
-  Expect.equals(f.fun<Y>(y), "FY"); /// 06: continued
-  Expect.equals(f.fun<Z>(z), "FZ"); /// 06: continued
+  Expect.equals(d.fun<Y>(y), "D"); //# 02: continued
+  Expect.equals(e.fun<Y>(y), "E"); //# 04: continued
+  Expect.equals(f.fun<Y>(y), "FY"); //# 05: continued
+  Expect.equals(f.fun<Z>(z), "FZ"); //# 05: continued
+  Expect.equals(f.fun<Y>(y), "FY"); //# 06: continued
+  Expect.equals(f.fun<Z>(z), "FZ"); //# 06: continued
 }