[clang] [CIR][CUDA][HIP] Skip alias emission when the aliasee is not emitted (PR #234627)

[Steffen Larsen via cfe-commits]

https://github.com/steffenlarsen commented:

Looks like a carbon copy of the OGCG variant, so LGTM. I would like more testing though and it would be good to have codeowners eyes as well.

https://github.com/llvm/llvm-project/pull/234627