Add CoreRT ifdefs around RyuJIT-specific intrinsic attributes to fix break in .NET Native for UWP
Add CoreRT ifdefs around RyuJIT-specific intrinsic attributes to fix break in .NET Native for UWP

[tfs-changeset: 1560551]

krytarowski/corert,yizhang82/corert,manu-silicon/corert,krytarowski/corert,kyulee1/corert,yizhang82/corert,mjp41/corert,schellap/corert,botaberg/corert,kyulee1/corert,botaberg/corert,schellap/corert,yizhang82/corert,schellap/corert,mjp41/corert,botaberg/corert,yizhang82/corert,botaberg/corert,shrah/corert,mjp41/corert,shrah/corert,gregkalapos/corert,manu-silicon/corert,shrah/corert,krytarowski/corert,sandreenko/corert,tijoytom/corert,shrah/corert,gregkalapos/corert,manu-silicon/corert,tijoytom/corert,kyulee1/corert,sandreenko/corert,sandreenko/corert,tijoytom/corert,mjp41/corert,mjp41/corert,krytarowski/corert,manu-silicon/corert,kyulee1/corert,schellap/corert,gregkalapos/corert,manu-silicon/corert,schellap/corert,gregkalapos/corert,sandreenko/corert,tijoytom/corert