Make telemetry_unittests.py work on Windows

testing/scripts/telemetry_unittests.py

 #!/usr/bin/env python
 # 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 json
 import os
 import sys
 
 
 import common
 
 
 def main_run(args):
   filter_tests = []
   if args.filter_file:
     filter_tests = json.load(args.filter_file)
 
   with common.temporary_file() as tempfile_path:
     rc = common.run_command([
+        sys.executable,
         os.path.join(args.paths['build'], 'scripts', 'tools', 'runit.py'),
         '--show-path',
         os.path.join(args.paths['build'], 'scripts', 'slave', 'runtest.py'),
         '--target', args.build_config_fs,
         '--xvfb',
         '--annotate', 'gtest',
         '--test-type', 'telemetry_unittests',
         '--builder-name', args.properties['buildername'],
         '--slave-name', args.properties['slavename'],
         '--build-number', str(args.properties['buildnumber']),
@@ skipping 22 matching lines @@
 def main_compile_targets(args):
   json.dump(['chrome'], args.output)
 
 
 if __name__ == '__main__':
   funcs = {
     'run': main_run,
     'compile_targets': main_compile_targets,
   }
   sys.exit(common.run_script(sys.argv[1:], funcs))