[clang] [llvm] [clang][ssaf] Add the TUSummaryExtractorRegistry (PR #173290)

[Balázs Benics via llvm-commits]

steakhal wrote:

Does anyone know why my `SummaryExtractorRegistryTest.InvokingExtractors` fails in the CI, but does not fail on my Mac?

I also feel like my expectation is right, given that `ASTConsumers` in a `std::vector` should destruct in reverse order; thus the side effects of logging should reflect this.

https://github.com/llvm/llvm-project/pull/173290