This is an extremely cheap function (just checks that the coin CTxOut
isn't null) that doesn't need to be gated on check_ratio.
This is a partial backport of [[https://github.com/bitcoin/bitcoin/pull/22677 | core#22677]]
https://github.com/bitcoin/bitcoin/pull/22677/commits/64e4963c635ec3a73a5fa3f32f6ec08e70609f60
Depends on D12443