[flang] [llvm] [mlir] [flang] Implement workdistribute construct lowering (PR #140523)

[Ivan R. Ivanov via llvm-commits]

ivanradanov wrote:

I am not sure the using rewrite patterns is suitable here - mainly because we have a list of transformations we know we need to do in what order so there is no need to involve patterns which add additional overhead and complexity (guarding against matching again etc, making sure the order is correct). That's how the LowerWorkshare pass is implemented.

https://github.com/llvm/llvm-project/pull/140523