[flang] [llvm] [flang][OpenMP] Decompose compound constructs, do recursive lowering (PR #90098)

[Sergio Afonso via llvm-commits]

https://github.com/skatrak approved this pull request.

Thank you Krzysztof for working on this and addressing my comments. LGTM.

https://github.com/llvm/llvm-project/pull/90098