test: improve code in test-http-host-headers

* use common.fail to handle errors
* remove console.log
* use arrow functions

PR-URL: nodejs#10830
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-http-host-headers.js

@@ -1,11 +1,10 @@
 'use strict';
-require('../common');
+const common = require('../common');
 const http = require('http');
 const assert = require('assert');
 const httpServer = http.createServer(reqHandler);
 
 function reqHandler(req, res) {
-  console.log('Got request: ' + req.headers.host + ' ' + req.url);
   if (req.url === '/setHostFalse5') {
     assert.strictEqual(req.headers.host, undefined);
   } else {
@@ -14,14 +13,9 @@ function reqHandler(req, res) {
                  req.headers.host);
   }
   res.writeHead(200, {});
-  //process.nextTick(function() { res.end('ok'); });
   res.end('ok');
 }
 
-function thrower(er) {
-  throw er;
-}
-
 testHttp();
 
 function testHttp() {
@@ -30,59 +24,52 @@ function testHttp() {
 
   function cb(res) {
     counter--;
-    console.log('back from http request. counter = ' + counter);
     if (counter === 0) {
       httpServer.close();
     }
     res.resume();
   }
 
-  httpServer.listen(0, function(er) {
-    console.error(`test http server listening on ${this.address().port}`);
+  httpServer.listen(0, (er) => {
     assert.ifError(er);
     http.get({
       method: 'GET',
       path: '/' + (counter++),
       host: 'localhost',
-      //agent: false,
-      port: this.address().port,
+      port: httpServer.address().port,
       rejectUnauthorized: false
-    }, cb).on('error', thrower);
+    }, cb).on('error', common.fail);
 
     http.request({
       method: 'GET',
       path: '/' + (counter++),
       host: 'localhost',
-      //agent: false,
-      port: this.address().port,
+      port: httpServer.address().port,
       rejectUnauthorized: false
-    }, cb).on('error', thrower).end();
+    }, cb).on('error', common.fail).end();
 
     http.request({
       method: 'POST',
       path: '/' + (counter++),
       host: 'localhost',
-      //agent: false,
-      port: this.address().port,
+      port: httpServer.address().port,
       rejectUnauthorized: false
-    }, cb).on('error', thrower).end();
+    }, cb).on('error', common.fail).end();
 
     http.request({
       method: 'PUT',
       path: '/' + (counter++),
       host: 'localhost',
-      //agent: false,
-      port: this.address().port,
+      port: httpServer.address().port,
       rejectUnauthorized: false
-    }, cb).on('error', thrower).end();
+    }, cb).on('error', common.fail).end();
 
     http.request({
       method: 'DELETE',
       path: '/' + (counter++),
       host: 'localhost',
-      //agent: false,
-      port: this.address().port,
+      port: httpServer.address().port,
       rejectUnauthorized: false
-    }, cb).on('error', thrower).end();
+    }, cb).on('error', common.fail).end();
   });
 }