[llvm] [nfc][mlgo] Incrementally update DominatorTreeAnalysis in FunctionPropertiesAnalysis (PR #104867)

[Reid Kleckner via llvm-commits]

rnk wrote:

The patch doesn't have new tests, but is presumably exercised by all the inliner tests. Can you remind us how the dominator tree analysis is checked for correctness? Why should we be confident that the new dominator tree is correct? Is it validated in regular +asserts builds, or is it covered under expensive checks? Have you run the test suite with that validation ahead of time, or which bot would we monitor post submit to see if it comes back green?

https://github.com/llvm/llvm-project/pull/104867