Suite names were not being used because `test` has to have access to it
during instantiation - this PR cleans things up a little while at the
same time upgrading unittest2.
Other changes:
Renamed the `EIP_4844_FORK_*` config constants to `DENEB_FORK_*` as
this matches the latest spec and it's already used in the official
Sepolia config.
* consolidate consensus spec transition test fixtures
* include capella
* consoliate fork test fixtures
* note change in EIP-4844 process_block in alpha.2