This first MR create an internal structured representation of the CFG and computes the domination relationship. Over a few other MRs I will implement an algorithm inspired to [this article](https://medium.com/leaningtech/solving-the-structured-control-flow-problem-o...) to compute a better structure than the one we already have, but for the moment the computed data is immediately wasted.
-- v2: vkd3d-shader/ir: Dump the domination relationship. vkd3d-shader/ir: Compute the domination relationship.