This builds on top of the target-independent cost model added in D124269
to add aarch64 specific costs for fptoui_sat and fptosi_sat intrinsics.
For many common types they will be legal instructions as the AArch64
instructions will saturate naturally. For unsupported pairs of integer
and floating point types, an additional min/max clamp is needed.
Differential Revision: https://reviews.llvm.org/D124357
2dcb2d8562