[m140] Pretty print jobs.json

Cherry-pick of https://review.skia.org/1056297

Change-Id: Ica1c0cc6e777ac0605ff3004c382be01dcf74816
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/1056357
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
2 files changed