Rewrite isolate_smoke_test.py to increase the coverage.

tools/isolate/isolate.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 """Does one of the following depending on the --mode argument:
   check     Verifies all the inputs exist, touches the file specified with
             --result and exits.
   hashtable Puts a manifest file and hard links each of the inputs into the
             output directory.
@@ skipping 159 matching lines @@
       filemode &= ~(stat.S_IWGRP | stat.S_IWOTH)
       if read_only:
         filemode &= ~stat.S_IWUSR
       if filemode & stat.S_IXUSR:
         filemode |= (stat.S_IXGRP | stat.S_IXOTH)
       else:
         filemode &= ~(stat.S_IXGRP | stat.S_IXOTH)
       outdict[infile]['mode'] = filemode
       outdict[infile]['size'] = filestats.st_size
       # Used to skip recalculating the hash. Use the most recent update time.
-      outdict[infile]['timestamp'] = int(round(
-          max(filestats.st_mtime, filestats.st_ctime)))
+      outdict[infile]['timestamp'] = int(round(filestats.st_mtime))
       # If the timestamp wasn't updated, carry on the sha-1.
       if (prevdict.get(infile, {}).get('timestamp') ==
           outdict[infile]['timestamp'] and
           'sha-1' in prevdict[infile]):
         # Reuse the previous hash.
         outdict[infile]['sha-1'] = prevdict[infile]['sha-1']
 
     if level >= WITH_HASH and not outdict[infile].get('sha-1'):
       h = hashlib.sha1()
       with open(filepath, 'rb') as f:
@@ skipping 331 matching lines @@
         command,
         relative_dir,
         options.result)
   except run_test_from_archive.MappingError, e:
     print >> sys.stderr, str(e)
     return 1
 
 
 if __name__ == '__main__':
   sys.exit(main())