[AArch64][GlobalISel] Improve lowering of vector fp16 fpext#165554

HolyMolyCowMan wants to merge 1 commit intollvm:mainllvm/llvm-project:mainfrom

HolyMolyCowMan:fp16-fpext-loweringHolyMolyCowMan/llvm-project:fp16-fpext-loweringCopy head branch name to clipboard