Fix Re-Org Back into Canonical Chain hive test (erigontech#5647)

Co-authored-by: Alexey Sharp <alexeysharp@Alexeys-iMac.local>

ethdb/privateapi/ethbackend.go

@@ -470,6 +470,18 @@ func (s *EthBackendServer) getQuickPayloadStatusIfPossible(blockHash common.Hash
 			log.Debug(fmt.Sprintf("[%s] Downloading some other PoS stuff", prefix), "hash", blockHash)
 			return &engineapi.PayloadStatus{Status: remote.EngineStatus_SYNCING}, nil
 		}
+		// Following code ensures we skip the fork choice state update if if forkchoiceState.headBlockHash references an ancestor of the head of canonical chain
+		headHash := rawdb.ReadHeadBlockHash(tx)
+		if err != nil {
+			return nil, err
+		}
+
+		// We add the extra restriction blockHash != headHash for the FCU case of canonicalHash == blockHash
+		// because otherwise (when FCU points to the head) we want go to stage headers
+		// so that it calls writeForkChoiceHashes.
+		if blockHash != headHash && canonicalHash == blockHash {
+			return &engineapi.PayloadStatus{Status: remote.EngineStatus_VALID, LatestValidHash: blockHash}, nil
+		}
 	}
 
 	// If another payload is already commissioned then we just reply with syncing