EIP-5656 Mcopy

Documentation for tests/cancun/eip5656_mcopy.

Generate fixtures for these test cases for Cancun with:

Cancun only:

fill -v tests/cancun/eip5656_mcopy --fork=Cancun --evm-bin=/path/to/evm-tool-dev-version

For all forks up to and including Cancun:

fill -v tests/cancun/eip5656_mcopy --until=Cancun --evm-bin=/path/to/evm-tool-dev-version

Cross-client EIP-5656 Tests