Move parser and token related libraries into their own subfolder.

tests/compiler/dart2js/backend_dart/dart_printer_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.
 
 library dart_printer_test;
 
 import 'dart:mirrors';
 import 'package:expect/expect.dart';
 import 'package:compiler/src/constants/values.dart';
 import 'package:compiler/src/dart_backend/backend_ast_nodes.dart';
 import 'package:compiler/src/dart_backend/backend_ast_to_frontend_ast.dart'
     show TreePrinter;
 import 'package:compiler/src/diagnostics/diagnostic_listener.dart';
 import 'package:compiler/src/diagnostics/messages.dart';
 import 'package:compiler/src/diagnostics/spannable.dart' show Spannable;
-import 'package:compiler/src/scanner/listener.dart';
-import 'package:compiler/src/scanner/parser.dart';
+import 'package:compiler/src/parser/listener.dart';
+import 'package:compiler/src/parser/parser.dart';
 import 'package:compiler/src/scanner/scanner.dart';
-import 'package:compiler/src/scanner/token.dart';
+import 'package:compiler/src/tokens/token.dart';
 import 'package:compiler/src/io/source_file.dart';
 import 'package:compiler/src/string_validator.dart';
 import 'package:compiler/src/tree/tree.dart' show DartString;
 import 'package:compiler/src/tree/tree.dart' as tree;
 
 /// For debugging the [AstBuilder] stack. Prints information about [x].
 void show(x) {
   StringBuffer buf = new StringBuffer();
   Unparser unparser = new Unparser(buf);
   void unparse(x) {
@@ skipping 943 matching lines @@
   checkStatement("do while(x); while (y);");
   checkStatement("{do; while(x); while (y);}");
 
   checkStatement('switch(x) { case 1: case 2: return y; }');
   checkStatement('switch(x) { default: return y; }');
   checkStatement('switch(x) { case 1: x=y; default: return y; }');
   checkStatement('switch(x) { case 1: x=y; y=z; break; default: return y; }');
 
 }