[flang-commits] [flang] [flang][OpenMP] Implement iterator that flattens BLOCK constructs (PR #180981)

[Krzysztof Parzyszek via flang-commits]

kparzysz wrote:

This replaces the former `LoopRange` iterator with a similar, extended functionality.  Two pieces of functionality were removed:
1. The new iterator can only move forward.
2. The auto-detection of constness was removed, the new iterator is effectively an extension of `parser::Block::const_iterator`.

https://github.com/llvm/llvm-project/pull/180981