[task scheduler] Add simple program to validate tasks and jobs
[task scheduler] Add simple program to validate tasks and jobs

Change-Id: If8206fe0995dfa5a442450b0221896c15d85aed9
Reviewed-on: https://skia-review.googlesource.com/c/192013
Commit-Queue: Ben Wagner <3ef7217be91069877d94f7907ce5479000772cd3@google.com>
Auto-Submit: Ben Wagner <3ef7217be91069877d94f7907ce5479000772cd3@google.com>
Reviewed-by: Eric Boren <0e499112533c8544f0505ea0d08394fb5ad7d8fa@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot