EIP-7939 Count Leading Zeros

Documentation for tests/osaka/eip7939_count_leading_zeros@v5.0.0.

Generate fixtures for these test cases for Osaka with:

fill -v tests/osaka/eip7939_count_leading_zeros --fork Osaka

Tests EIP-7939: Count leading zeros (CLZ) opcode

Test cases for EIP-7939: Count leading zeros (CLZ) opcode.