!fixup test: fix test-beforeexit-event

Trying to use a net server here is not reasonable, instead try with a
file.

test/parallel/test-beforeexit-event.js

@@ -1,6 +1,6 @@
 'use strict';
 var assert = require('assert');
-var net = require('net');
+var fs = require('fs');
 var util = require('util');
 var common = require('../common');
 var revivals = 0;
@@ -23,18 +23,18 @@ function tryTimer() {
   setTimeout(function() {
     console.log('timeout cb, do another once beforeExit');
     revivals++;
-    process.once('beforeExit', tryListen);
+    process.once('beforeExit', tryFile);
   }, 1);
 }
 
-function tryListen() {
-  console.log('create a server');
-  net.createServer()
-    .listen(common.PORT)
-    .on('listening', function() {
-      revivals++;
-      this.close();
-    });
+function tryFile() {
+  console.log('open a file');
+  fs.open(__filename, 'r', (err, fd) => {
+    if (err) throw err;
+
+    revivals++;
+    fs.closeSync(fd);
+  });
 }
 
 process.on('exit', function() {