emulators/xsystem35: switch to WWW to Wayback Machine

Homepage link http://8ne.sakura.ne.jp:20008/chika/unitbase/xsys35/ is
dead (Connect timeout (60 seconds)) for more than a month and should
be replaced by alive link (or link to archive.org as a last resort).

Reported by: Repology

(cherry picked from commit 0b3131e162f4707cd81d0e78e73266c233061f7a)