cmd/evm: add state transition tool for testing (#20958)

This PR implements the EVM state transition tool, which is intended
to be the replacement for our retesteth client implementation.
Documentation is present in the cmd/evm/README.md file.

Co-authored-by: Felix Lange <fjl@twurst.com>

cmd/evm/main.go

@@ -22,6 +22,7 @@ import (
 	"math/big"
 	"os"
 
+	"github.com/ethereum/go-ethereum/cmd/evm/internal/t8ntool"
 	"github.com/ethereum/go-ethereum/cmd/utils"
 	"gopkg.in/urfave/cli.v1"
 )
@@ -126,6 +127,27 @@ var (
 	}
 )
 
+var stateTransitionCommand = cli.Command{
+	Name:    "transition",
+	Aliases: []string{"t8n"},
+	Usage:   "executes a full state transition",
+	Action:  t8ntool.Main,
+	Flags: []cli.Flag{
+		t8ntool.TraceFlag,
+		t8ntool.TraceDisableMemoryFlag,
+		t8ntool.TraceDisableStackFlag,
+		t8ntool.OutputAllocFlag,
+		t8ntool.OutputResultFlag,
+		t8ntool.InputAllocFlag,
+		t8ntool.InputEnvFlag,
+		t8ntool.InputTxsFlag,
+		t8ntool.ForknameFlag,
+		t8ntool.ChainIDFlag,
+		t8ntool.RewardFlag,
+		t8ntool.VerbosityFlag,
+	},
+}
+
 func init() {
 	app.Flags = []cli.Flag{
 		BenchFlag,
@@ -156,13 +178,18 @@ func init() {
 		disasmCommand,
 		runCommand,
 		stateTestCommand,
+		stateTransitionCommand,
 	}
 	cli.CommandHelpTemplate = utils.OriginCommandHelpTemplate
 }
 
 func main() {
 	if err := app.Run(os.Args); err != nil {
+		code := 1
+		if ec, ok := err.(*t8ntool.NumberedError); ok {
+			code = ec.Code()
+		}
 		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
+		os.Exit(code)
 	}
 }