test: change object assign to spread object

change object assign to spread object in test-npm-install.js
PR-URL: #30422
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

Author: putxe

test/parallel/test-npm-install.js

@@ -38,12 +38,12 @@ const pkgPath = path.join(installDir, 'package.json');
 
 fs.writeFileSync(pkgPath,pkgContent);
 
-constenv=Object.assign({},process.env,{
-PATH: path.dirname(process.execPath),
-NPM_CONFIG_PREFIX: path.join(npmSandbox,'npm-prefix'),
-NPM_CONFIG_TMP: path.join(npmSandbox,'npm-tmp'),
-HOME: homeDir,
-});
+constenv={ ...process.env,
+PATH: path.dirname(process.execPath),
+NPM_CONFIG_PREFIX: path.join(npmSandbox,'npm-prefix'),
+NPM_CONFIG_TMP: path.join(npmSandbox,'npm-tmp'),
+HOME: homeDir,
+};
 
 exec(`${process.execPath}${npmPath} install`,{
 cwd: installDir,