Exclude any *_test.dart and */test/*dart when creating stamp files for pkg and third_party/pkg.

pkg/pkg_files.gyp

 # 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.
 
 {
   'targets': [
     # Other targets depend on pkg files, but have too many inputs, which causes
     # issues on some platforms.
     # This target lists all the files in pkg and third_party/pkg,
     # and creates the timestamp pkg_files.stamp, which depends on some
     # intermediate helper timestamps.
     # We split third_party/pkg up into three groups, based on the last
     # character before .dart at the end of the filename.
     {
       'target_name': 'pkg_files_stamp',
       'type': 'none',
       'actions': [
         {
           'action_name': 'make_pkg_files_stamp',
           'inputs': [
             '../tools/create_timestamp_file.py',
-            '<!@(["python", "../tools/list_files.py", "\\.dart$", "."])',
+            '<!@(["python", "../tools/list_files.py",'
+                '"^(?!.*/test/).*(?<!_test)[.]dart$",'
+                '"."])',
             '<(SHARED_INTERMEDIATE_DIR)/third_party_pkg_files_1.stamp',
             '<(SHARED_INTERMEDIATE_DIR)/third_party_pkg_files_2.stamp',
             '<(SHARED_INTERMEDIATE_DIR)/third_party_pkg_files_3.stamp',
           ],
           'outputs': [
             '<(SHARED_INTERMEDIATE_DIR)/pkg_files.stamp',
           ],
           'action': [
             'python', '../tools/create_timestamp_file.py',
             '<@(_outputs)',
@@ skipping 44 matching lines @@
           ],
           'action': [
             'python', '../tools/create_timestamp_file.py',
             '<@(_outputs)',
           ],
         },
       ],
     },
   ],
 }