[llvm] [Support] Assert that DomTree nodes share parent (PR #101198)

[Alexis Engelke via llvm-commits]

aengelke wrote:

I think this is caused by unclean(ccache-ed?) builds. I was able to reproduce locally at first, but in a clean working dir (with clean ccache), it worked fine.

I think the root cause is #102180, where `std::conditional_t` is now used depending on `GraphHasNodeNumbers<NodeT *>`. With a non-clean recompile, this apparently evaluates to different values in different files, causing accesses to the same field at different offsets.

Not sure how to fix the bots.

https://github.com/llvm/llvm-project/pull/101198