[flang] [llvm] [Flang][OpenMP] Defer descriptor mapping for assumed dummy argument types (PR #154349)

[via llvm-commits]

agozillon wrote:

thank you very much for the reviews @ergawy @TIFitis I am going to rebase and update the PR and then land it now (provided the CI still passes of course)

https://github.com/llvm/llvm-project/pull/154349