test: refactor test-child-process-ipc

Change var to const or let.
Change assert.equal() to assert.strictEqual().
PR-URL: #9990
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>

Author: malenesok007

test/parallel/test-child-process-ipc.js

@@ -1,17 +1,18 @@
 'use strict';
-varcommon=require('../common');
-varassert=require('assert');
 
-varspawn=require('child_process').spawn;
+constcommon=require('../common');
+constassert=require('assert');
 
-varpath=require('path');
+constspawn=require('child_process').spawn;
 
-varsub=path.join(common.fixturesDir,'echo.js');
+constpath=require('path');
 
-vargotHelloWorld=false;
-vargotEcho=false;
+constsub=path.join(common.fixturesDir,'echo.js');
 
-varchild=spawn(process.argv[0],[sub]);
+letgotHelloWorld=false;
+letgotEcho=false;
+
+constchild=spawn(process.argv[0],[sub]);
 
 child.stderr.on('data',function(data){
 console.log('parent stderr: '+data);
@@ -23,7 +24,7 @@ child.stdout.on('data', function(data) {
 console.log('child said: '+JSON.stringify(data));
 if(!gotHelloWorld){
 console.error('testing for hello world');
-assert.equal('hello world\r\n',data);
+assert.strictEqual('hello world\r\n',data);
 gotHelloWorld=true;
 console.error('writing echo me');
 child.stdin.write('echo me\r\n');