Fixes an off by 1 error where `EIP170_CODE_SIZE_LIMIT` was being treated as the
lowest invalid value by EVM code, but the highest valid value by witness code.
To remove confusion, this is renamed to `EIP170_MAX_CODE_SIZE` with value
0x6000, which matches the name (`MAX_CODE_SIZE`) and value used for this limit
in [EIP-170](https://eips.ethereum.org/EIPS/eip-170).
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Jamie Lokier
jangko