test: refactor test-net-reconnect-error

* var -> const/let
* assert.equal() -> assert.strictEqual()
PR-URL: #9903
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>

Author: Duy Le

test/parallel/test-net-reconnect-error.js

@@ -1,13 +1,13 @@
 'use strict';
-varcommon=require('../common');
-varnet=require('net');
-varassert=require('assert');
-varN=20;
-varclient_error_count=0;
-vardisconnect_count=0;
+constcommon=require('../common');
+constnet=require('net');
+constassert=require('assert');
+constN=20;
+letclient_error_count=0;
+letdisconnect_count=0;
 
 // Hopefully nothing is running on common.PORT
-varc=net.createConnection(common.PORT);
+constc=net.createConnection(common.PORT);
 
 c.on('connect',function(){
 console.error('CLIENT connected');
@@ -17,7 +17,7 @@ c.on('connect', function() {
 c.on('error',function(e){
 console.error('CLIENT error: '+e.code);
 client_error_count++;
-assert.equal('ECONNREFUSED',e.code);
+assert.strictEqual('ECONNREFUSED',e.code);
 });
 
 c.on('close',function(){
@@ -27,6 +27,6 @@ c.on('close', function() {
 });
 
 process.on('exit',function(){
-assert.equal(N+1,disconnect_count);
-assert.equal(N+1,client_error_count);
+assert.strictEqual(N+1,disconnect_count);
+assert.strictEqual(N+1,client_error_count);
 });