Use 127.0.0.1 as the default host for the standalone server (#52283)

This helps getting rid of the

```
Error: connect ECONNREFUSED ::1:64696
    at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1494:16) {
  errno: -61,
  code: 'ECONNREFUSED',
  syscall: 'connect',
  address: '::1',
  port: 64696
}
```

error for me when running the standalone server. cc @ijjk.

I'm not sure if it's related to http-party/node-http-proxy#835.

Co-authored-by: JJ Kasper <22380829+ijjk@users.noreply.github.com>

packages/next/src/server/lib/render-server-standalone.ts

@@ -69,7 +69,9 @@ export const createServerHandler = async ({
   didInitialize = true
 
   const getProxyServer = (pathname: string) => {
-    const targetUrl = `http://${hostname}:${routerPort}${pathname}`
+    const targetUrl = `http://${
+      hostname === 'localhost' ? '127.0.0.1' : hostname
+    }:${routerPort}${pathname}`
     const proxyServer = httpProxy.createProxy({
       target: targetUrl,
       changeOrigin: false,