[llvm] [ValueTracking] Don't limit the recursion depth for single-incoming phis in isKnownNonZero (PR #226173)

[Nikita Popov via llvm-commits]

nikic wrote:

This should probably also have a non-PhaseOrdering test somewhere?

We use a similar pattern to limit phi recursion in lots of other places in ValueTracking though --- I think if we update one of them, we should probably update all of them for consistent behavior?

https://github.com/llvm/llvm-project/pull/226173