test(integration): properly pipe turbopack binary stdouts (#46382)

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Partially resolves WEB-628

Starting next-dev relies on some stdout status to grab its devserver
url, and this PR correctly bubbles up custom turbopack binary's stdout
to make it work.

packages/next/src/build/swc/index.ts

@@ -424,13 +424,17 @@ function loadNative(isCustomTurbopack = false) {
 
               let child = spawn(__INTERNAL_CUSTOM_TURBOPACK_BINARY, args, {
                 stdio: 'pipe',
-                env: {
-                  ...process.env,
-                },
               })
               child.on('message', (message: any) => {
-                console.log(message)
+                require('console').log(message)
               })
+              child.stdout.on('data', (data: any) => {
+                require('console').log(data.toString())
+              })
+              child.stderr.on('data', (data: any) => {
+                require('console').log(data.toString())
+              })
+
               child.on('close', (code: any) => {
                 if (code !== 0) {
                   reject({

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

@@ -461,7 +461,9 @@ If you cannot make the changes above, but still want to try out\nNext.js v13 wit
     // Start preflight after server is listening and ignore errors:
     preflight().catch(() => {})
 
-    await telemetry.flush()
+    if (!isCustomTurbopack) {
+      await telemetry.flush()
+    }
     return server
   } else {
     // we're using a sub worker to avoid memory leaks. When memory usage exceeds 90%, we kill the worker and restart it.