core, eth, internal, rpc: implement final block (#24282)

* eth: core: implement finalized block

* eth/catalyst: fix final block

* eth/catalyst: update finalized head gauge

* internal/jsre/deps: updated web3.js to allow for finalized block

* eth/catalyst: make sure only one thread can call fcu

* eth/catalyst: nitpicks

* eth/catalyst: use plain mutex

* eth: nitpicks

rpc/types.go

@@ -61,9 +61,10 @@ type jsonWriter interface {
 type BlockNumber int64
 
 const (
-	PendingBlockNumber  = BlockNumber(-2)
-	LatestBlockNumber   = BlockNumber(-1)
-	EarliestBlockNumber = BlockNumber(0)
+	FinalizedBlockNumber = BlockNumber(-3)
+	PendingBlockNumber   = BlockNumber(-2)
+	LatestBlockNumber    = BlockNumber(-1)
+	EarliestBlockNumber  = BlockNumber(0)
 )
 
 // UnmarshalJSON parses the given JSON fragment into a BlockNumber. It supports:
@@ -88,6 +89,9 @@ func (bn *BlockNumber) UnmarshalJSON(data []byte) error {
 	case "pending":
 		*bn = PendingBlockNumber
 		return nil
+	case "finalized":
+		*bn = FinalizedBlockNumber
+		return nil
 	}
 
 	blckNum, err := hexutil.DecodeUint64(input)
@@ -112,6 +116,8 @@ func (bn BlockNumber) MarshalText() ([]byte, error) {
 		return []byte("latest"), nil
 	case PendingBlockNumber:
 		return []byte("pending"), nil
+	case FinalizedBlockNumber:
+		return []byte("finalized"), nil
 	default:
 		return hexutil.Uint64(bn).MarshalText()
 	}
@@ -158,6 +164,10 @@ func (bnh *BlockNumberOrHash) UnmarshalJSON(data []byte) error {
 		bn := PendingBlockNumber
 		bnh.BlockNumber = &bn
 		return nil
+	case "finalized":
+		bn := FinalizedBlockNumber
+		bnh.BlockNumber = &bn
+		return nil
 	default:
 		if len(input) == 66 {
 			hash := common.Hash{}