[clang] [clang] fix half && bfloat16 convert node expr codegen (PR #89051)

[Craig Topper via cfe-commits]

topperc wrote:

> > @JinjinLi868 are you still working on this?
> 
> yes, i am. could you give me some advice and can i help you ?

Can we have a scalar only patch as @arsenm requested?

https://github.com/llvm/llvm-project/pull/89051