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>

params/config.go

@@ -135,6 +135,27 @@ var (
 		Clique:                        nil,
 	}
 
+	AllDevChainProtocolChanges = &ChainConfig{
+		ChainID:                       big.NewInt(1337),
+		HomesteadBlock:                big.NewInt(0),
+		EIP150Block:                   big.NewInt(0),
+		EIP155Block:                   big.NewInt(0),
+		EIP158Block:                   big.NewInt(0),
+		ByzantiumBlock:                big.NewInt(0),
+		ConstantinopleBlock:           big.NewInt(0),
+		PetersburgBlock:               big.NewInt(0),
+		IstanbulBlock:                 big.NewInt(0),
+		MuirGlacierBlock:              big.NewInt(0),
+		BerlinBlock:                   big.NewInt(0),
+		LondonBlock:                   big.NewInt(0),
+		ArrowGlacierBlock:             big.NewInt(0),
+		GrayGlacierBlock:              big.NewInt(0),
+		ShanghaiTime:                  newUint64(0),
+		TerminalTotalDifficulty:       big.NewInt(0),
+		TerminalTotalDifficultyPassed: true,
+		IsDevMode:                     true,
+	}
+
 	// AllCliqueProtocolChanges contains every protocol change (EIPs) introduced
 	// and accepted by the Ethereum core developers into the Clique consensus.
 	AllCliqueProtocolChanges = &ChainConfig{
@@ -280,8 +301,9 @@ type ChainConfig struct {
 	TerminalTotalDifficultyPassed bool `json:"terminalTotalDifficultyPassed,omitempty"`
 
 	// Various consensus engines
-	Ethash *EthashConfig `json:"ethash,omitempty"`
-	Clique *CliqueConfig `json:"clique,omitempty"`
+	Ethash    *EthashConfig `json:"ethash,omitempty"`
+	Clique    *CliqueConfig `json:"clique,omitempty"`
+	IsDevMode bool          `json:"isDev,omitempty"`
 }
 
 // EthashConfig is the consensus engine configs for proof-of-work based sealing.