[llvm] [Instrumentation] Fix EdgeCounts vector size in SetBranchWeights (PR #99064)

[Ellis Hoag via llvm-commits]

ellishg wrote:

@avikivity I'm not able to reproduce the error. It seems strange that you are getting the error "Do not know how to promote this operator!" since I think that might be during lowing to assembly, which should not happen with `-emit-llvm`.

https://github.com/llvm/llvm-project/pull/99064