[llvm] Fix scalar overload name constructed by ReplaceWithVeclib.cpp (PR #111095)

[Tex Riddell via llvm-commits]

tex3d wrote:

Note: buildkite failure is an ongoing unrelated failure with:
```
RuntimeError: __cxx03/__algorithm/adjacent_find.h: Header cxx03 is not a valid header
```

https://github.com/llvm/llvm-project/pull/111095