Don't use the old generated files.

tests/stub-generator/testcfg.py

 # Copyright (c) 2011, 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 os
 import re
 import shutil
 import sys
 import tempfile
 
@@ skipping 69 matching lines @@
 
 class DartStubTestConfiguration(test_configuration.StandardTestConfiguration):
   def __init__(self, context, root):
     super(DartStubTestConfiguration, self).__init__(context, root)
 
   def ListTests(self, current_path, path, mode, arch):
     dartc = self.context.GetDartC(mode, 'dartc')
     self.context.generate = os.access(dartc[0], os.X_OK)
     tests = []
     for root, dirs, files in os.walk(join(self.root, 'src')):
+      # Skip remnants from the subdirectory that used to be used for
+      # generated code.
+      if root.endswith('generated'):
+        continue
       for f in [x for x in files if self.IsTest(x)]:
         # If we can generate code, do not use the checked-in generated
         # code.  Conversely, if we cannot, then only use the
         # checked-in generated code.
         if self.context.generate == f.endswith('-generatedTest.dart'):
           continue
         test_path = current_path + [ f[:-5] ]  # Remove .dart suffix.
         if not self.Contains(path, test_path):
           continue
         tests.append(DartStubTestCase(self.context,
                                       test_path,
                                       join(root, f),
                                       mode,
                                       arch))
     return tests
 
 
 def GetConfiguration(context, root):
   return DartStubTestConfiguration(context, root)