[llvm] [DominanceFrontier] make iterating dereferenced DominanceFrontierBase::find deterministic (PR #69711)

[Jakub Kuderski via llvm-commits]

https://github.com/kuhar commented:

Right, `set<ptr>` is as good as `unordered_set<ptr>`. Would be nice to have a test that expects a specific order regardless of pointer values.

https://github.com/llvm/llvm-project/pull/69711