HistoryDatabase: improve migration code.

1. Delete old migration code. Chromium generally doesn't support
forward-migrating data that is more than 2 years old. This change
deletes migration code that has been live for at least two years. This
reduces binary bloat (-17kB on Android arm32) and removes some migration
anti-patterns, which hopefully will help prevent future code being added
that uses these patterns. See crbug.com/409355667

2. Use compatible version correctly. This value is meant to represent
the oldest version of Chromium *code* that can use the current version
of Chromium *data*, i.e. support for downgrades. Chromium generally
doesn't attempt to support downgrading, but the migrations to v69 and
v70 were backwards compatible, so code for 68 should be fine to run with
data from 69+. This value was not actually being set at all previously.

3. Handle failure to update meta table.

Bug: 409355667, 40891923
Change-Id: I9901f1d5117e726c116575d742229c6201e70303
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6442189
Reviewed-by: Etienne Bergeron <etienneb@chromium.org>
Reviewed-by: manuk hovanesian <manukh@chromium.org>
Commit-Queue: Evan Stade <evanstade@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#1447350}