Allow Dart package.stamp file to be missing in dart2js_nobuild recipe

scripts/slave/recipes/dart/dart2js_nobuild.py

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 DEPS = [
   'depot_tools/bot_update',
   'file',
   'depot_tools/gclient',
   'gsutil',
   'recipe_engine/path',
@@ skipping 99 matching lines @@
     build_dir = api.path['checkout'].join(build_directories[api.platform.name])
     build_dir = api.path.abspath(build_dir)
     api.file.makedirs('Create build directory', build_dir)
     api.file.rmtree('Clean build directory', build_dir)
     api.zip.unzip('Unzip sdk', zipfile, build_dir)
 
   # Build only the package links. Once we remove this target, build nothing.
   if api.platform.name == 'mac':
     api.file.remove('Mark package links as out-of-date',
       api.path.abspath(api.path['checkout'].join(
-        'xcodebuild', 'DerivedSources', 'ReleaseX64', 'packages.stamp')))
+        'xcodebuild', 'DerivedSources', 'ReleaseX64', 'packages.stamp')),
+      ok_ret='any')
   build_args = ['-mrelease', '--arch=x64', 'packages']
   api.python('build dart',
              api.path['checkout'].join('tools', 'build.py'),
              args=build_args,
              cwd=api.path['checkout'])
 
   with api.step.defer_results():
     # Special hard-coded steps with compiler=none, run on selected runtimes
     if runtime == 'jsshell' and system == 'linux' and sharded:
       IsFirstTestStep = False
@@ skipping 85 matching lines @@
       api.properties.generic(
         mastername='client.dart',
         buildername='dart2js-linux-drt-93-105-dev',
         revision='hash_of_revision'))
    yield (
       api.test('dart2js-mac10.11-safari-1-3-be') + api.platform('mac', 64) +
       api.properties.generic(
         mastername='client.dart',
         buildername='dart2js-mac10.11-safari-1-3-be',
         revision='hash_of_revision'))