child_process: remove extra shallow copy

PR-URL: https://github.com/nodejs/node/pull/27801
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/child_process.js

@@ -559,7 +559,7 @@ function spawnSync(file, args, options) {
     maxBuffer: MAX_BUFFER,
     ...opts.options
   };
-  options = opts.options = Object.assign(defaults, opts.options);
+  options = opts.options = defaults;
 
   debug('spawnSync', opts.args, options);