Split collecting and traversing.

tests/compiler/dart2js/unparser_test.dart

 // Copyright (c) 2012, 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.
 
 #import('dart:uri');
 #import('parser_helper.dart');
 #import('mock_compiler.dart');
 #import("../../../lib/compiler/compiler.dart");
 #import("../../../lib/compiler/implementation/dart_backend/dart_backend.dart");
 #import("../../../lib/compiler/implementation/elements/elements.dart");
@@ skipping 418 matching lines @@
 
 main() {
   topgetset;
   topgetset = 6;
 
   mylib.topgetset;
   mylib.topgetset = 5;
 }
 ''';
   var expectedResult =
-    'get p_topgetset=> 5;'
+    'get topgetset=> 5;'
+    'set topgetset(arg){}'
+    'get p_topgetset=> 6;'
     'set p_topgetset(arg){}'
-    'get topgetset=> 6;'
-    'set topgetset(arg){}'
-    'main(){topgetset; topgetset=6; p_topgetset; p_topgetset=5;}';
+    'main(){p_topgetset; p_topgetset=6; topgetset; topgetset=5;}';
   testDart2DartWithLibrary(mainSrc, librarySrc,
       (String result) { Expect.equals(expectedResult, result); });
 }
 
 testFieldTypeOutput() {
   testDart2Dart('main(){new A().field;}class B{}class A{B field;}');
 }
 
 testDefaultClassNamePlaceholder() {
   var src = '''
@@ skipping 47 matching lines @@
   //testConflictSendsRename();
   testNoConflictSendsRename();
   testConflictLibraryClassRename();
   testDefaultClassWithArgs();
   testClassExtendsWithArgs();
   testStaticInvocation();
   testLibraryGetSet();
   testFieldTypeOutput();
   testDefaultClassNamePlaceholder();
 }