[clang] [lld] [llvm] [lld] Add support for sdata8 for FDE CIE (PR #174508)

[Farid Zakaria via cfe-commits]

fzakaria wrote:

> Does this work with LTO?
> 
> Should we turn this on by default with medium code model?

@efriedma-quic I think it's simpler to just turn on for medium code model but it does come with the additional space consideration which is why I set it as a separate toggle for the initial pass.
I am open to both;

https://github.com/llvm/llvm-project/pull/174508