Ignore test files in 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 to many inputs, which causes
     # issues on some platforms.
     # This target lists all the files in pkg and third_party/pkg,
     # and creates a single pkg_files.stamp
@@ skipping 13 matching lines @@
           ],
           'action': [
             'python', '../tools/create_timestamp_file.py',
             '<@(_outputs)',
           ],
         },
         {
           'action_name': 'make_third_party_pkg_files_stamp',
           'inputs': [
             '../tools/create_timestamp_file.py',
-            '<!@(["python", "../tools/list_files.py", "^(?!.*pub/test).*dart$",'
+            '<!@(["python", "../tools/list_files.py",'
+                '"^(?!.*_test.dart).*dart$",'
                 '"../third_party/pkg"])',
           ],
           'outputs': [
             '<(SHARED_INTERMEDIATE_DIR)/third_party_pkg_files.stamp',
           ],
           'action': [
             'python', '../tools/create_timestamp_file.py',
             '<@(_outputs)',
           ],
         },
       ],
     },
   ],
 }