Revert "fix: detect JetBrains running on local ipv6 (#11653)" (#11664)

This reverts commit 2d61d5332a.

scripts/echoserver/main.go

@@ -9,21 +9,10 @@ import (
 	"io"
 	"log"
 	"net"
-	"os"
 )
 
 func main() {
-	network := os.Args[1]
-	var address string
-	switch network {
-	case "tcp4":
-		address = "127.0.0.1"
-	case "tcp6":
-		address = "[::]"
-	default:
-		log.Fatalf("invalid network: %s", network)
-	}
-	l, err := net.Listen(network, address+":0")
+	l, err := net.Listen("tcp", "127.0.0.1:0")
 	if err != nil {
 		log.Fatalf("listen error: err=%s", err)
 	}