chromium_tests: remove unnecessary path component from cache checkout path

scripts/slave/recipe_modules/chromium_tests/api.py

 # Copyright 2014 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.
 
 import collections
 import contextlib
 import copy
 import itertools
 import json
 
@@ skipping 145 matching lines @@
 
     kwargs = {}
     try:
       builder_cache = self.m.path['builder_cache']
     except KeyError:  # no-op if builder cache is not set up.
       pass
     else:
       sanitized_buildername = ''.join(
           c if c.isalnum() else '_' for c in self.m.properties['buildername'])
       checkout_path = builder_cache.join(
-          'checkouts', sanitized_buildername)
+          bot_config.get('checkout_dir', sanitized_buildername))
       self.m.shutil.makedirs('checkout path', checkout_path)
       kwargs['cwd'] = checkout_path
 
     # Bot Update re-uses the gclient configs.
     update_step = self.m.bot_update.ensure_checkout(
         patch_root=bot_config.get('patch_root'),
         root_solution_revision=root_solution_revision,
         clobber=bot_config.get('clobber', False),
         force=force, **kwargs)
     assert update_step.json.output['did_run']
@@ skipping 652 matching lines @@
   def get_compile_targets_for_scripts(self):
     return self.m.python(
         name='get compile targets for scripts',
         script=self.m.path['checkout'].join(
             'testing', 'scripts', 'get_compile_targets.py'),
         args=[
             '--output', self.m.json.output(),
             '--',
         ] + self.get_common_args_for_scripts(),
         step_test_data=lambda: self.m.json.test_api.output({}))