Fix build failure caused by timezone issue in tests.

Timestamps in pretty-printed job status use the local timezone.
Jenkins machines use GMT as their local time; so the time printed
on jenkins differs from times printed elsewhere.

This fix fuzzes out the time in the timestamps, so that it doesn't matter
where the test is run.

Bugs closed: aurora-684

Reviewed at https://reviews.apache.org/r/25350/
Preserve executor HealthCheckerThread name

Testing Done:

$ ./build-support/python/isort-run
$ ./build-support/python/checkstyle-check
$ ./pants ./src/test/python/apache/aurora/executor:all

Bugs closed: AURORA-682

Reviewed at https://reviews.apache.org/r/25337/
Add a factory to produce OneWayUpdate instances based on job state and update settings.

Bugs closed: AURORA-613

Reviewed at https://reviews.apache.org/r/25356/