[Attributor][FIX] Use liveness information of the right function

When we use liveness for edges during the `genericValueTraversal` we
need to make sure to use the AAIsDead of the correct function. This
patch adds the proper logic and some simple caching scheme. We also
add an assertion to the `isEdgeDead` call to make sure future misuse
is detected earlier.

Fixes https://github.com/llvm/llvm-project/issues/53872