This move/refactor is needed to set up a decent unittest for UTXO snapshot activation.
This is a backport of [[https://github.com/bitcoin/bitcoin/pull/19806 | core#19806]] [1/8]
https://github.com/bitcoin/bitcoin/pull/19806/commits/6606a4f8c616cf256537c3bfbdade9b43c51b4f5