PEORIA, Ariz. — Cactus League results will be forgotten by the end of March. That never changes. The heroes of spring go down in forgotten history. But what happens within these games matters far more for the Padres this year than in the lead-up to recent seasons. The performance of many players over the next three weeks will go a long way toward determining who is still around by the end of March. The Padres play their spring training opener on Thursday against the Dodgers, 27 days before the teams meet in their season-opening series in Seoul, South Korea. And so commences in earnest the Padr…