[autotest] A script for launching and killing swarming bots.

* This script launch and kill swarming bots on an autotest server.
* This swarming bots will pull requests from
chromeos-proxy.appspot.com and execute the requests.
* Each request would be a run_suite or abort_suite command.
  other requests will be rejected.

BUG=chromium:516253
TEST=Run the script to launch and kill bots.

Change-Id: I4d5944fda657e33bbd5e046df8fc4a50d3b1c709
Reviewed-on: https://chromium-review.googlesource.com/290135
Tested-by: Fang Deng <fdeng@chromium.org>
Reviewed-by: Dan Shi <dshi@chromium.org>
Reviewed-by: Marc-Antoine Ruel <maruel@chromium.org>
Commit-Queue: Fang Deng <fdeng@chromium.org>
4 files changed