[llvm] Add assertions to to check dominator tree is not called on empty functions (PR #167428)

[Matt Arsenault via llvm-commits]

arsenm wrote:

Is this still necessary? I thought the main way this happened was for functions that hit the global isel fallback, which is now avoided in ad1a45b903b87f8e0c36a20f054d170ff2b5b2d5

https://github.com/llvm/llvm-project/pull/167428