accounts/abi: enable struct golang binding generation (#18491)

* accounts/abi, cmd/abigen: support tuple

accounts/abi/bind, cmd/abigen: add objc back

accounts/abi/bind: use byte[24] as function indicator

accounts/abi/bind: resolve struct slice or array

accounts/abi/bind: remove sort logic

accounts: fix issues in abi

* accounts/abi: address comment

cmd/abigen/main.go

@@ -69,6 +69,8 @@ func main() {
 		lang = bind.LangGo
 	case "java":
 		lang = bind.LangJava
+	case "objc":
+		lang = bind.LangObjC
 	default:
 		fmt.Printf("Unsupported destination language \"%s\" (--lang)\n", *langFlag)
 		os.Exit(-1)