[clang] [llvm] [Offload] Unify offloading entries into a single section (PR #125731)

[Artem Belevich via cfe-commits]

https://github.com/Artem-B approved this pull request.

LGTM syntax-wise. Don't have much of an opinion on the strategy.

Are there existing users for this? Should we worry about providing backward compatibility with the "omp" sections in the existing binaries?

https://github.com/llvm/llvm-project/pull/125731