test: remove duplicate checks in pummel/test-timers

Remove checks in pummel/test-timers that are already checked in
parallel/test-timers-clear-null-does-not-throw-error.

PR-URL: https://github.com/nodejs/node/pull/34473


Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>