node/chainstate: Remove do/while loop

Summary:
Partial backport of core#23280:
https://github.com/bitcoin/bitcoin/pull/23280/commits/adf4912d77496b9a243476c5944528f95641f14d?diff=split&w=1

Depends on D12568.

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D12569