Similar to run_all.sh (I299c0ab5dc3dea4841e560d8fb95b8f3e7df89f2),
produce a runtime stat for each run of the cloud launcher.
Although it won't directly highlight errors, problems tend to end this
playbook early. When graphed with grafana, we could have noticed a
large drop in the average runtime which would have suggested a
problem.
Change-Id: I8e5371cbc94e9a803ea5e64ae94aca293b834c73
e32a9fdd0f