[clang] [llvm] [Frontend] Add leaf constructs and association to OpenMP/ACC directives (PR #83625)

[Valentin Clement バレンタイン クレメン via cfe-commits]

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

Looks good to me from the OpenACC point of view. Someone from OpenMP should approve as well.

https://github.com/llvm/llvm-project/pull/83625