Add support for overrides on the consistency tests.

Also includes new |last_updated| fields on usage limit and bedtime entries and a lot of test cases.

Bug: 935711
Change-Id: I589216931896d22f106b9a241ab3e81c5ce48108
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1518947
Commit-Queue: G. Silva <gfaus@chromium.org>
Reviewed-by: Aga Wronska <agawronska@chromium.org>
Reviewed-by: Henrique Grandinetti <hgrandinetti@chromium.org>
Cr-Commit-Position: refs/heads/master@{#641192}
12 files changed