tests based on
- 8ca383c9e0/python/elec-p2sh-hodl.py
- 8ca383c9e0/python/elec-p2wsh-hodl.py
note: I could not reproduce the signature for the p2wsh cltv spend linked above,
so I have created a new testnet output and spent that for that test (to make sure
our behaviour is consensus-valid).