AArch64/ARM64: add non-scalar lowering for more FCVT operations.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206591 91177308-0d34-0410-b5e6-96231b3b80d8
AArch64/ARM64: port more AArch64 tests to ARM64.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206592 91177308-0d34-0410-b5e6-96231b3b80d8