[clang] [llvm] [clang][CodeGen] Generate follow-up metadata for loops in correct format (PR #131985)

[Michael Kruse via cfe-commits]

Meinersbur wrote:

> ```c
> #pragma omp simd reduction(+:v0)
> #pragma unroll(4)
> ```

That's not supposed to work. I think in the past the unroll pragma was just dropped. If the debug info is the issue, there hasn't been a lot of care to get OpenMP emit correct debug info, see e.g. #110700.  

For this reason OpenMP 5.1 added new pragma:
```c
#pragma omp simd reduction(+:v0)
#pragma omp unroll partial(4)
```


https://github.com/llvm/llvm-project/pull/131985