[llvm] [LLVM] Fix typo in branch-weights.ll test CEHCK->CHECK (PR #113574)

[Chris Apple via llvm-commits]

cjappl wrote:

Requesting review from @MatzeB as the original person who committed this change. 

This fix seems reasonable to me, but I want to make sure it wasn't intentionally disabled for some reason

https://github.com/llvm/llvm-project/pull/113574