test:refactor test-tls-hello-parser-failure

* setTimeout() with no duration -> setImmediate()
* add common.mustCall() where appropriate
* var -> const
* .on() -> .once()

PR-URL: https://github.com/nodejs/node/pull/9715
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

test/parallel/test-tls-hello-parser-failure.js

@@ -1,46 +1,43 @@
 'use strict';
-var common = require('../common');
-var assert = require('assert');
+
+const common = require('../common');
 
 if (!common.hasCrypto) {
   common.skip('missing crypto');
   return;
 }
-var tls = require('tls');
 
-var net = require('net');
-var fs = require('fs');
+const assert = require('assert');
+const tls = require('tls');
+
+const net = require('net');
+const fs = require('fs');
 
-var options = {
+const options = {
   key: fs.readFileSync(common.fixturesDir + '/test_key.pem'),
   cert: fs.readFileSync(common.fixturesDir + '/test_cert.pem')
 };
 
-var bonkers = Buffer.alloc(1024 * 1024, 42);
+const bonkers = Buffer.alloc(1024 * 1024, 42);
 
-var server = tls.createServer(options, function(c) {
+const server = tls.createServer(options, function(c) {
 
-}).listen(0, function() {
-  var client = net.connect(this.address().port, function() {
+}).listen(0, common.mustCall(function() {
+  const client = net.connect(this.address().port, common.mustCall(function() {
     client.write(bonkers);
-  });
+  }));
 
-  var once = false;
-
-  var writeAgain = setTimeout(function() {
+  const writeAgain = setImmediate(function() {
     client.write(bonkers);
   });
 
-  client.on('error', function(err) {
-    if (!once) {
-      clearTimeout(writeAgain);
-      once = true;
+  client.once('error', common.mustCall(function(err) {
+    clearImmediate(writeAgain);
     client.destroy();
     server.close();
-    }
-  });
+  }));
 
-  client.on('close', function(hadError) {
+  client.on('close', common.mustCall(function(hadError) {
     assert.strictEqual(hadError, true, 'Client never errored');
-  });
-});
+  }));
+}));