[Chronik] Fix "Node and Chronik diverged" when both are fully synced

Summary:
Currently the node logs "Node and Chronik diverged" at startup even when both are fully synced.

Now it doesn't log that, and doesn't rewind_indexer in this case.

Test Plan: ninja && ./test/functional/test_runner.py chronik_resync

Reviewers: Fabien, #bitcoin_abc

Reviewed By: Fabien, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D13958