Remove support for multivm branch and runners

tools/dartium/upload_steps.py

 #!/usr/bin/python
 
 # Copyright (c) 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.
 
 """Steps to archive dartium, content_shell, and chromedriver from buildbots.
 
-Imported by buildbot_annotated_steps.py and multivm_archive.py
+Imported by buildbot_annotated_steps.py
 """
 
 import imp
 import os
 import platform
 import re
 import subprocess
 import sys
 
 import dartium_bot_utils
@@ skipping 249 matching lines @@
 def RemoveArchives(archives):
   """Remove the list of archives in Google storage.
   """
   for archive in archives:
     if archive.find(GS_SITE) == 0:
       cmd = [GSUTIL, 'rm', archive.rstrip()]
       (status, _) = ExecuteCommand(cmd)
       if status != 0:
         return status
   return 0