v8.0.0 release testing checklist

[jimmygchen]

• Test builder flow with --builder-disable-ssz to cover JSON code path
  • Fix get_header JSON deserialization. #8228
• Test reconstruction delay on networks with different slot times
  • Max reconstruction delay as a function of slot time #8067
• Make sure blob RPC serving still work around Fulu epoch boundaries
  • Avoid attempting to serve blobs after Fulu fork #7756
• Make sure data columns are getting pruned on devnet-3
  • #6853 Adding store tests for data column pruning #7228
• Monitor attestation publishing performance after the PR below is merged dropped from v8 as we didn't see consistent improvements
  • Use OnceCell in HotHDiffBufferCache #8176
• Test semi-supernode flag
  • Add --semi-supernode support #8254
• Test switching to semi-supernode and supernode
  • Trigger backfill on startup if user switches to a supernode or semi-supernode #8265