Adding android device info dumps on hosts for buildbot display

R=luqui@google.com, navabi@google.com, zty@google.com, navabi@chromium.org
BUG=

Review URL: https://codereview.chromium.org/921163005

Cr-Commit-Position: refs/heads/master@{#316366}

build/android/buildbot/bb_device_status_check.py

@@ -336,6 +336,10 @@ def main():
     types, builds, batteries, reports, errors, fail_step_lst, json_data = (
         zip(*[DeviceInfo(dev, options) for dev in devices]))
 
+  # Write device info to file for buildbot info display.
+  with open('/tmp/adb_device_info', 'w') as outfile:
+    json.dump(json_data, outfile)
+
   err_msg = CheckForMissingDevices(options, devices) or []
 
   unique_types = list(set(types))