Fix Capella fork test assertions

Author: hwwhww

specs/capella/beacon-chain.md

@@ -242,7 +242,7 @@ class BeaconState(Container):
     current_sync_committee: SyncCommittee
     next_sync_committee: SyncCommittee
     # Execution
-    latest_execution_payload_header: ExecutionPayloadHeader
+    latest_execution_payload_header: ExecutionPayloadHeader  # [Modified in Capella]
     # Withdrawals
     next_withdrawal_index: WithdrawalIndex  # [New in Capella]
     next_withdrawal_validator_index: ValidatorIndex  # [New in Capella]

tests/core/pyspec/eth2spec/test/helpers/capella/fork.py

@@ -29,14 +29,12 @@ def run_fork_test(post_spec, pre_state):
         'inactivity_scores',
         # Sync
         'current_sync_committee', 'next_sync_committee',
-        # Execution
-        'latest_execution_payload_header',
     ]
     for field in stable_fields:
         assert getattr(pre_state, field) == getattr(post_state, field)
 
     # Modified fields
-    modified_fields = ['fork']
+    modified_fields = ['fork', 'latest_execution_payload_header']
     for field in modified_fields:
         assert getattr(pre_state, field) != getattr(post_state, field)