Enable superfluous ws.port flag to fix some Hive RPC tests (#8909)

### Context
**Websocket port flag**
Hive tests for RPC suite depend on the (geth) default 8546 port. So,
opening one more listener for this additional port if `ws.port` was
specified. This flag isn't used in Erigon, as it shares port with http
listener. Normally, one may not specify and it offers no other benefit.

cmd/rpcdaemon/cli/config.go

@@ -630,6 +630,27 @@ func startRegularRpcServer(ctx context.Context, cfg *httpcfg.HttpCfg, rpcAPI []r
 		return err
 	}
 
+	// Separate Websocket handler if websocket port flag specified
+	if cfg.WebsocketEnabled && cfg.WebsocketPort != cfg.HttpPort {
+		wsEndpoint := fmt.Sprintf("tcp://%s:%d", cfg.HttpListenAddress, cfg.WebsocketPort)
+		wsApiHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			if isWebsocket(r) {
+				wsHandler.ServeHTTP(w, r)
+			}
+		})
+		wsListener, wsAddr, err := node.StartHTTPEndpoint(wsEndpoint, &node.HttpEndpointConfig{Timeouts: cfg.HTTPTimeouts}, wsApiHandler)
+		if err != nil {
+			return fmt.Errorf("could not start separate Websocket RPC api at port %d: %w", cfg.WebsocketPort, err)
+		}
+		info = append(info, "websocket.url", wsAddr)
+		defer func() {
+			shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+			defer cancel()
+			_ = wsListener.Shutdown(shutdownCtx)
+			logger.Info("HTTP endpoint closed", "url", wsAddr)
+		}()
+	}
+
 	if cfg.HttpServerEnabled {
 		httpEndpoint := fmt.Sprintf("tcp://%s:%d", cfg.HttpListenAddress, cfg.HttpPort)
 		if cfg.HttpURL != "" {

cmd/rpcdaemon/cli/httpcfg/http_cfg.go

@@ -43,6 +43,7 @@ type HttpCfg struct {
 	API                  []string
 	Gascap               uint64
 	MaxTraces            uint64
+	WebsocketPort        int
 	WebsocketEnabled     bool
 	WebsocketCompression bool
 	RpcAllowListFilePath string

turbo/cli/default_flags.go

@@ -63,6 +63,7 @@ var DefaultFlags = []cli.Flag{
 	&utils.HTTPVirtualHostsFlag,
 	&utils.AuthRpcVirtualHostsFlag,
 	&utils.HTTPApiFlag,
+	&utils.WSPortFlag,
 	&utils.WSEnabledFlag,
 	&utils.WsCompressionFlag,
 	&utils.HTTPTraceFlag,

turbo/cli/flags.go

@@ -387,7 +387,7 @@ func setEmbeddedRpcDaemon(ctx *cli.Context, cfg *nodecfg.Config, logger log.Logg
 			IdleTimeout:  ctx.Duration(HTTPIdleTimeoutFlag.Name),
 		},
 		EvmCallTimeout:              ctx.Duration(EvmCallTimeoutFlag.Name),
-
+		WebsocketPort:               ctx.Int(utils.WSPortFlag.Name),
 		WebsocketEnabled:            ctx.IsSet(utils.WSEnabledFlag.Name),
 		RpcBatchConcurrency:         ctx.Uint(utils.RpcBatchConcurrencyFlag.Name),
 		RpcStreamingDisable:         ctx.Bool(utils.RpcStreamingDisableFlag.Name),