Missing eip-2124 / EIP-6122 testing for fork combination possibilities

[kdeme]

ForkId logic as described here https://eips.ethereum.org/EIPS/eip-2124#stale-software-examples
is not properly tested and I am not sure that our way of implementation (https://github.com/status-im/nimbus-eth1/blob/master/execution_chain/common/hardforks.nim#L371-L387) covers all that (aside from the existing bug of #3794)

See also test cases here: https://github.com/ethereum/go-ethereum/blob/0413af40f60290cf689b4ecca4e51fef0ec11119/core/forkid/forkid_test.go#L158

or in EIPS
https://eips.ethereum.org/EIPS/eip-2124
https://eips.ethereum.org/EIPS/eip-6122
https://eips.ethereum.org/EIPS/eip-2364

It is also the case that we might need to do some changes to be able to test this in that same way.

[kdeme]

Fixed in #3803 and #3796