[clang] [CIR] Reject unlowered language address spaces on CIR globals (PR #223660)

[David Rivera via cfe-commits]

https://github.com/RiverDave approved this pull request.

I haven't checked if out `TargetLowering` would ever leave these leftovers, but this is a nice addition. Thanks!

https://github.com/llvm/llvm-project/pull/223660