fa320975411af4f0e41771d89958a77fd7a2284b test: Create cached blocks not in the future (MarcoFalke)
Pull request description:
This avoids test failures when tests assume blocks are not from the future, like in wallet_dump: https://cirrus-ci.com/task/6607130193035264?command=ci#L3306
ACKs for top commit:
jonatack:
ACK fa320975411af4f0e41771d89958a77fd7a2284b
Tree-SHA512: 60b6882e0e1df8c5d67f034533407a45d3685983891b67ff4631072bfd0a93a325c7ca18758d7a2df252e4fcdb7c87321cb1e84458b22782e57e719eec634c22
Backport of Core PR18641