[Arm64/Unix] Revise JIT_MemCpy (#11143)
[Arm64/Unix] Revise JIT_MemCpy (#11143)

* [Arm64/Unix] Revise JIT_MemCpy

Use ldp/stp
Correctly handle short copy lengths
Simplify code & pseudo code
Use uint*_t to make pseudo code more readable

pgavlin/coreclr,AlexGhiondea/coreclr,cshung/coreclr,poizan42/coreclr,russellhadley/coreclr,pgavlin/coreclr,pgavlin/coreclr,krk/coreclr,dpodder/coreclr,alexperovich/coreclr,wateret/coreclr,sagood/coreclr,ruben-ayrapetyan/coreclr,tijoytom/coreclr,gkhanna79/coreclr,qiudesong/coreclr,kyulee1/coreclr,cshung/coreclr,kyulee1/coreclr,yizhang82/coreclr,wtgodbe/coreclr,qiudesong/coreclr,wtgodbe/coreclr,JosephTremoulet/coreclr,AlexGhiondea/coreclr,botaberg/coreclr,ragmani/coreclr,YongseopKim/coreclr,krytarowski/coreclr,hseok-oh/coreclr,wateret/coreclr,wtgodbe/coreclr,James-Ko/coreclr,parjong/coreclr,yeaicc/coreclr,mskvortsov/coreclr,gkhanna79/coreclr,cshung/coreclr,yeaicc/coreclr,pgavlin/coreclr,ruben-ayrapetyan/coreclr,kyulee1/coreclr,hseok-oh/coreclr,poizan42/coreclr,botaberg/coreclr,ragmani/coreclr,cshung/coreclr,yeaicc/coreclr,mskvortsov/coreclr,krk/coreclr,ruben-ayrapetyan/coreclr,kyulee1/coreclr,tijoytom/coreclr,wtgodbe/coreclr,hseok-oh/coreclr,russellhadley/coreclr,mmitche/coreclr,kyulee1/coreclr,dpodder/coreclr,alexperovich/coreclr,James-Ko/coreclr,alexperovich/coreclr,dpodder/coreclr,cydhaselton/coreclr,dpodder/coreclr,alexperovich/coreclr,yeaicc/coreclr,krytarowski/coreclr,AlexGhiondea/coreclr,yizhang82/coreclr,JonHanna/coreclr,krk/coreclr,YongseopKim/coreclr,ragmani/coreclr,kyulee1/coreclr,mmitche/coreclr,rartemev/coreclr,JosephTremoulet/coreclr,pgavlin/coreclr,sagood/coreclr,cydhaselton/coreclr,wateret/coreclr,wateret/coreclr,cydhaselton/coreclr,James-Ko/coreclr,yeaicc/coreclr,qiudesong/coreclr,dpodder/coreclr,mskvortsov/coreclr,russellhadley/coreclr,James-Ko/coreclr,cmckinsey/coreclr,AlexGhiondea/coreclr,krytarowski/coreclr,cmckinsey/coreclr,krytarowski/coreclr,poizan42/coreclr,rartemev/coreclr,rartemev/coreclr,botaberg/coreclr,cydhaselton/coreclr,AlexGhiondea/coreclr,mmitche/coreclr,poizan42/coreclr,cmckinsey/coreclr,rartemev/coreclr,cshung/coreclr,parjong/coreclr,dpodder/coreclr,qiudesong/coreclr,yizhang82/coreclr,James-Ko/coreclr,mskvortsov/coreclr,AlexGhiondea/coreclr,jamesqo/coreclr,rartemev/coreclr,mmitche/coreclr,jamesqo/coreclr,cmckinsey/coreclr,James-Ko/coreclr,YongseopKim/coreclr,botaberg/coreclr,yeaicc/coreclr,ragmani/coreclr,cmckinsey/coreclr,krytarowski/coreclr,botaberg/coreclr,qiudesong/coreclr,JosephTremoulet/coreclr,jamesqo/coreclr,jamesqo/coreclr,tijoytom/coreclr,alexperovich/coreclr,sagood/coreclr,cmckinsey/coreclr,rartemev/coreclr,russellhadley/coreclr,cydhaselton/coreclr,alexperovich/coreclr,yeaicc/coreclr,gkhanna79/coreclr,YongseopKim/coreclr,tijoytom/coreclr,JonHanna/coreclr,ruben-ayrapetyan/coreclr,poizan42/coreclr,hseok-oh/coreclr,JosephTremoulet/coreclr,russellhadley/coreclr,wtgodbe/coreclr,sagood/coreclr,JosephTremoulet/coreclr,YongseopKim/coreclr,hseok-oh/coreclr,parjong/coreclr,JosephTremoulet/coreclr,tijoytom/coreclr,JonHanna/coreclr,YongseopKim/coreclr,JonHanna/coreclr,ragmani/coreclr,ruben-ayrapetyan/coreclr,sagood/coreclr,krytarowski/coreclr,poizan42/coreclr,gkhanna79/coreclr,yizhang82/coreclr,wateret/coreclr,mskvortsov/coreclr,ruben-ayrapetyan/coreclr,yizhang82/coreclr,gkhanna79/coreclr,botaberg/coreclr,hseok-oh/coreclr,mmitche/coreclr,tijoytom/coreclr,krk/coreclr,qiudesong/coreclr,mskvortsov/coreclr,jamesqo/coreclr,mmitche/coreclr,krk/coreclr,cmckinsey/coreclr,JonHanna/coreclr,pgavlin/coreclr,parjong/coreclr,yizhang82/coreclr,JonHanna/coreclr,wateret/coreclr,parjong/coreclr,wtgodbe/coreclr,gkhanna79/coreclr,krk/coreclr,ragmani/coreclr,russellhadley/coreclr,parjong/coreclr,cshung/coreclr,cydhaselton/coreclr,sagood/coreclr,jamesqo/coreclr