test: replace forEach with for...of

PR-URL: https://github.com/nodejs/node/pull/50611
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

test/parallel/test-fs-mkdtemp-prefix-check.js

@@ -27,7 +27,7 @@ function failAsync(value) {
     });
 }
 
-prefixValues.forEach((prefixValue) => {
+for (const prefixValue of prefixValues) {
   fail(prefixValue);
   failAsync(prefixValue);
-});
+}