Test: Use core register API instead of hardcoding
Test: Use core register API instead of hardcoding

libretro/mgba,Iniquitatis/mgba,Iniquitatis/mgba,mgba-emu/mgba,mgba-emu/mgba,Iniquitatis/mgba,libretro/mgba,libretro/mgba,mgba-emu/mgba,Iniquitatis/mgba,mgba-emu/mgba,libretro/mgba,libretro/mgba