Revert "SDL: handle SDL_QUIT event"

[Parlane]

Reverts #2530

[dolphin-emu-bot]

FifoCI detected that this change impacts graphical rendering. Here are the behavior differences detected by the system:

• chibi-robo-fastdepth on ogl-lin-nv: diff
• chibi-robo-zfighting on ogl-lin-nv: diff
• djfny-menu on ogl-lin-nv: diff
• ea-vp6 on ogl-lin-nv: diff
• ed-lighting on ogl-lin-nv: diff
• fifa-street on ogl-lin-nv: diff
• fortune-street-fog on ogl-lin-nv: diff
• fortune-street-white-box on ogl-lin-nv: diff
• kirby-shadows on ogl-lin-nv: diff
• line-width-test on ogl-lin-nv: diff
• mario-tennis-menu on ogl-lin-nv: diff
• melee-lighting on ogl-lin-nv: diff
• mini-ninjas on ogl-lin-nv: diff
• monkeyball-fuse on ogl-lin-nv: diff
• mtennis-zfreeze on ogl-lin-nv: diff
• nfsu-purplerect on ogl-lin-nv: diff
• nfsu-reflections on ogl-lin-nv: diff
• nsmbw-intro on ogl-lin-nv: diff
• rs2-glass on ogl-lin-nv: diff
• sadx-ui on ogl-lin-nv: diff
• sf-assault-flashing on ogl-lin-nv: diff
• simpsons-tev on ogl-lin-nv: diff
• smg2-fog on ogl-lin-nv: diff
• soa-black on ogl-lin-nv: diff
• sw3-dt on ogl-lin-nv: diff
• thps4-shadow on ogl-lin-nv: diff
• tos-invis-char on ogl-lin-nv: diff
• xenoblade-menu on ogl-lin-nv: diff
• zww-waves on ogl-lin-nv: diff

_{^{automated-fifoci-reporter}}