[AArch64] Don't blindly lower f16/f128 FCCMPs.

Instead, extend f16 (like we do when lowering a standalone SETCC),
and let f128 be legalized to the RT calls.

Fixes PR26803.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263301 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed