dart2js cps: Clean up in type propagation.

tests/compiler/dart2js/analyze_unused_dart2js_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.
 
 library analyze_unused_dart2js;
 
 import 'package:async_helper/async_helper.dart';
 
 import 'package:compiler/src/dart2jslib.dart';
 import 'package:compiler/src/filenames.dart';
@@ skipping 32 matching lines @@
     "accept", "FunctionExpression", "CreateFunction"
   ],
 
   "lib/src/cps_ir/": const [
     "accept", "CreateFunction",
   ],
 
   "/lib/src/dart_backend/backend_ast_to_frontend_ast.dart": const [
     " is never "
   ],
-
-  "/lib/src/cps_ir/type_propagation.dart": const ["UnitTypeSystem"],
 };
 
 void main() {
   var uri = currentDirectory.resolve(
       'pkg/compiler/lib/src/use_unused_api.dart');
   asyncTest(() => analyze([uri], WHITE_LIST,
       analyzeAll: false, checkResults: checkResults));
 }
 
 bool checkResults(Compiler compiler, CollectingDiagnosticHandler handler) {
@@ skipping 15 matching lines @@
     } else if (member.isTypedef) {
       if (member.isResolved) {
         compiler.reportHint(member, MessageKind.GENERIC,
             {'text': "Helper typedef in production code '$member'."});
       }
     }
   }
   compiler.libraryLoader.lookupLibrary(helperUri).forEachLocalMember(checkLive);
   return handler.checkResults();
 }