perf: early return in getLocalhostAddressIfDiffersFromDNS when DNS order is verbatim (#22151)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: sapphi-red <49056869+sapphi-red@users.noreply.github.com>

Author: Copilot

packages/vite/src/node/utils.ts

@@ -922,17 +922,21 @@ export function unique<T>(arr: T[]): T[] {
  * Even if defaultResultOrder is `ipv4first`, `dns.lookup` result maybe same.
  * For example, when IPv6 is not supported on that machine/network.
  */
-export async function getLocalhostAddressIfDiffersFromDNS(): Promise<
-  string | undefined
-> {
-  const [nodeResult, dnsResult] = await Promise.all([
+export function getLocalhostAddressIfDiffersFromDNS():
+  | Promise<string | undefined>
+  | undefined {
+  if (dns.getDefaultResultOrder() === 'verbatim') {
+    return undefined
+  }
+  return Promise.all([
     dns.lookup('localhost'),
     dns.lookup('localhost', { verbatim: true }),
-  ])
-  const isSame =
-    nodeResult.family === dnsResult.family &&
-    nodeResult.address === dnsResult.address
-  return isSame ? undefined : nodeResult.address
+  ]).then(([nodeResult, dnsResult]) => {
+    const isSame =
+      nodeResult.family === dnsResult.family &&
+      nodeResult.address === dnsResult.address
+    return isSame ? undefined : nodeResult.address
+  })
 }
 
 export function diffDnsOrderChange(