Revert "benchmark: refactor helper into a class"

This reverts commit b70741e.

Refs: nodejs#31396
PR-URL: nodejs#31722
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Gus Caplan <[email protected]>
Reviewed-By: Vladimir de Turckheim <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>

Author: addaleax