Automatic merge from submit-queue

Fix possible panic in PodAffinityChecker

In `PodAffinityChecker.getMatchingAntiAffinityTerms()` `affinity.PodAntiAffinity` can be `nil` in this place. This problem occurs e.g. when `nil` is passed as `meta` to `PodAffinityChecker.InterPodAffinityMatches()`.

Stumbled upon it while working on #31136 (someone PTAL at that PR too, I've submitted it a month ago and seemingly no one noticed it), kube-controller-manager was crashing there.