cmd/geth: implement dev mode for post-merge (#27327)

This change adds back the 'geth --dev' mode of operation, using a cl-mocker. 

---------

Co-authored-by: Martin Holst Swende <martin@swende.se>
Co-authored-by: rjl493456442 <garyrong0905@gmail.com>
Co-authored-by: lightclient <14004106+lightclient@users.noreply.github.com>

cmd/utils/flags.go

@@ -160,7 +160,7 @@ var (
 		Usage:    "Ephemeral proof-of-authority network with a pre-funded developer account, mining enabled",
 		Category: flags.DevCategory,
 	}
-	DeveloperPeriodFlag = &cli.IntFlag{
+	DeveloperPeriodFlag = &cli.Uint64Flag{
 		Name:     "dev.period",
 		Usage:    "Block period to use in developer mode (0 = mine only if transaction pending)",
 		Category: flags.DevCategory,
@@ -1817,7 +1817,7 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *ethconfig.Config) {
 		log.Info("Using developer account", "address", developer.Address)
 
 		// Create a new developer genesis block or reuse existing one
-		cfg.Genesis = core.DeveloperGenesisBlock(uint64(ctx.Int(DeveloperPeriodFlag.Name)), ctx.Uint64(DeveloperGasLimitFlag.Name), developer.Address)
+		cfg.Genesis = core.DeveloperGenesisBlock(ctx.Uint64(DeveloperGasLimitFlag.Name), developer.Address)
 		if ctx.IsSet(DataDirFlag.Name) {
 			// If datadir doesn't exist we need to open db in write-mode
 			// so leveldb can create files.
@@ -1892,9 +1892,6 @@ func RegisterEthService(stack *node.Node, cfg *ethconfig.Config) (ethapi.Backend
 			Fatalf("Failed to create the LES server: %v", err)
 		}
 	}
-	if err := ethcatalyst.Register(stack, backend); err != nil {
-		Fatalf("Failed to register the Engine API service: %v", err)
-	}
 	stack.RegisterAPIs(tracers.APIs(backend.APIBackend))
 	return backend.APIBackend, backend
 }