From the PR description:
The last few commits contain significant test refactorings to make coins_tests easier to change in follow-ups.
test, refactor: Migrate GetCoinsMapEntry to return MaybeCoin
https://github.com/bitcoin/bitcoin/pull/30906/commits/ca74aa7490a5005d227da75dc8f2d1ab73c6e9d2
test: Group values and states in tests into CoinEntry wrappers
Note: that this commit affects the test order, but doesn't change its behavior or coverage otherwise.
https://github.com/bitcoin/bitcoin/pull/30906/commits/d5f8d607ab1f8fd9fc17aba4105867b450117be2
test: Validate error messages on fail
The ccoins_add and ccoins_write tests check the actual exception error messages now instead of just that they fail for the given parameters.
This enables us testing different exceptions in a more fine-grained way in later changes.
https://github.com/bitcoin/bitcoin/pull/30906/commits/c0b4b2c1eef95c0b626573a9a2e217f4a541a880
test, refactor: Remove remaining unbounded flags from coins_tests
https://github.com/bitcoin/bitcoin/pull/30906/commits/0a159f0914775756dcac2d9fa7fe4e4d4e70ba0c
test, refactor: Compact ccoins_access and ccoins_spend
Also added an extra check for AccessCoin in CheckAccessCoin to make sure its result is also validated.
https://github.com/bitcoin/bitcoin/pull/30906/commits/50cce20013c97e1257cb9f4c9319701a09b0a196
This concludes backport of core#30906
Depends on D18809