Add fork tests for Gloas

[StefanBratanov]

We seem to be missing the fork tests for Gloas. For reference, these are the Fulu fork tests:

https://github.com/ethereum/consensus-specs/tree/master/tests/core/pyspec/eth2spec/test/fulu/fork

[AbolareRoheemah]

Hi @jtraglia can I pick this up 🤲