test: refactor cluster-preload.js

PR-URL: #10701
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Italo A. Casas <me@italoacasas.com>

test/fixtures/cluster-preload.js

@@ -4,8 +4,8 @@ var assert = require('assert');
 // this module is used as a preload module. It should have a parent with the
 // module search paths initialized from the current working directory
 assert.ok(module.parent);
-var expectedPaths = require('module')._nodeModulePaths(process.cwd());
-assert.deepEqual(module.parent.paths, expectedPaths);
+const expectedPaths = require('module')._nodeModulePaths(process.cwd());
+assert.deepStrictEqual(module.parent.paths, expectedPaths);
 
 var cluster = require('cluster');
 cluster.isMaster || process.exit(42 + cluster.worker.id); // +42 to distinguish