sql: Add full state DCHECKs to Transaction.

The DCHECKs are intended to catch reusing a Transaction instance, and
speed up fixing Transaction usage errors with improved diagnostic
messages.

Change-Id: I984cf1dbea56141ac5717a7ecca1c5974879598a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3170944


Commit-Queue: Victor Costan <pwnall@chromium.org>
Reviewed-by: Ayu Ishii <ayui@chromium.org>
Cr-Commit-Position: refs/heads/main@{#923119}