[autotest] Add a task_runner shell script to help with testing.

This script is meant to be executed against a localhost test cluster.

TEST=Used the script.
BUG=chromium:425347

Change-Id: I2833cce83ebe7789fad7d08daf06661706137d16
Reviewed-on: https://chromium-review.googlesource.com/232524
Reviewed-by: Prashanth B <beeps@chromium.org>
Commit-Queue: Prashanth B <beeps@chromium.org>
Tested-by: Prashanth B <beeps@chromium.org>
1 file changed