misc: fix wrong next start start duration (vercel#56512)

This PR fixes `next start` and `next dev` so that they show the correct server boot-up time. The previous way of computing the start time was incorrect and misleading as it did not start exactly when next started.

Before:
> ✓ Ready in 120ms

After:
> ✓ Ready in 286ms

Author: feedthejim

packages/next/src/bin/next.ts

@@ -1,4 +1,5 @@
 #!/usr/bin/env node
+performance.mark('next-start')
 import '../server/require-hook'
 import * as log from '../build/output/log'
 import arg from 'next/dist/compiled/arg/index.js'

packages/next/src/build/utils.ts

@@ -1927,7 +1927,8 @@ export async function copyTracedFiles(
     serverOutputPath,
     `${
       moduleType
-        ? `import path from 'path'
+        ? `performance.mark('next-start');
+import path from 'path'
 import { fileURLToPath } from 'url'
 import module from 'module'
 const require = module.createRequire(import.meta.url)

packages/next/src/cli/next-start.ts

@@ -1,5 +1,4 @@
 #!/usr/bin/env node
-
 import '../server/lib/cpu-profile'
 import { startServer } from '../server/lib/start-server'
 import { getPort, printAndExit } from '../server/lib/utils'

packages/next/src/server/lib/start-server.ts

@@ -1,3 +1,6 @@
+if (performance.getEntriesByName('next-start').length === 0) {
+  performance.mark('next-start')
+}
 import '../next'
 import '../node-polyfill-fetch'
 import '../require-hook'
@@ -130,7 +133,6 @@ export async function startServer({
   envInfo,
   expFeatureInfo,
 }: StartServerOptions): Promise<void> {
-  const startServerProcessStartTime = Date.now()
   let handlersReady = () => {}
   let handlersError = () => {}
 
@@ -297,11 +299,17 @@ export async function startServer({
         upgradeHandler = initResult[1]
 
         const startServerProcessDuration =
-          Date.now() - startServerProcessStartTime
+          performance.mark('next-start-end') &&
+          performance.measure(
+            'next-start-duration',
+            'next-start',
+            'next-start-end'
+          ).duration
+
         const formatDurationText =
           startServerProcessDuration > 2000
             ? `${Math.round(startServerProcessDuration / 100) / 10}s`
-            : `${startServerProcessDuration}ms`
+            : `${Math.round(startServerProcessDuration)}ms`
 
         handlersReady()
         logStartInfo({