DefaultAttrIntrinsics was introduced to add very common attributes to a
large set of intrinsics.
Currently the added attributes include:
nofree nosync nounwind willreturn
I think those should hold for most AArch64 target intrinsics, but
there are too many to check manually. This patch makes most AArch64 target
Some notable exceptions I think are exclusive loads and stores as well
as the memory barrier intrinsics, for which nosync does not apply I