[clang] [flang] [llvm] [openmp] [Flang][OpenMP] Move builtin .mod generation into runtimes (PR #137828)

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

clementval wrote:

Can your remove the [OpenMP] from the title? This is misleading because it's all the flang module and not only related to OpenMP. 

https://github.com/llvm/llvm-project/pull/137828