correct THREAD_STATE_THREAD register for arm64 on darwin
correct THREAD_STATE_THREAD register for arm64 on darwin

bgould/avian,minor-jason/avian,dicej/avian,minor-jason/avian,MaartenR/avian,lwahlmeier/avian,ucdseniordesign/avian,bigfatbrowncat/avian-pack.avian,joshuawarner32/avian,lwahlmeier/avian,marcinolawski/avian,minor-jason/avian,lwahlmeier/avian,dicej/avian,bigfatbrowncat/avian-pack.avian,marcinolawski/avian,MaartenR/avian,MaartenR/avian,lostdj/avian,bgould/avian,MaartenR/avian,ucdseniordesign/avian,lostdj/avian,joshuawarner32/avian,minor-jason/avian,bigfatbrowncat/avian-pack.avian,lwahlmeier/avian,lostdj/avian,ucdseniordesign/avian,marcinolawski/avian,joshuawarner32/avian,bgould/avian,lostdj/avian,bgould/avian,dicej/avian,dicej/avian,joshuawarner32/avian,marcinolawski/avian,ucdseniordesign/avian,bigfatbrowncat/avian-pack.avian