[llvm] Fix SPIR-V function ordering violation in linker (PR #145039)

[Paulius Velesko via llvm-commits]

pvelesko wrote:

> Also, there is a danger that the reordering done in the linker may be undone by follow up transformation passes.

that seems like a separate issue.  

https://github.com/llvm/llvm-project/pull/145039