child_process: use kEmptyObject

PR-URL: nodejs#43159
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: Antoine du Hamel <[email protected]>

Author: LiviaMedeiros

lib/child_process.js

@@ -43,10 +43,11 @@ const {
 } = primordials;
 
 const {
-  promisify,
   convertToValidSignal,
   createDeferredPromise,
-  getSystemErrorName
+  getSystemErrorName,
+  kEmptyObject,
+  promisify,
 } = require('internal/util');
 const { isArrayBufferView } = require('internal/util/types');
 let debug = require('internal/util/debuglog').debuglog(
@@ -510,7 +511,7 @@ function normalizeSpawnArguments(file, args, options) {
   }
 
   if (options === undefined)
-    options = {};
+    options = kEmptyObject;
   else
     validateObject(options, 'options');