Support Constantinople properly

The current Constantinople implementation was done before the hard fork was finalised. As a result it is incompatible -- it implements some features, lacks others and perhaps even has incompatible implementation for some changes.

Without this it is not possible to run evmjit on Ethereum's mainnet.

However, in order to test this, EVMC should be updated to ABI6, see #180.

Start by reviewing the Constantinople implementation and the ABI6 update required by #180. Compare the implementation with the finalized hard fork changes, including missing or incompatible features; done means EVMC ABI6 testing passes and evmjit can run on Ethereum mainnet.

Written by the indexing model from the issue text.