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

[Avi Kivity via llvm-commits]

avikivity wrote:

Interesting,  in https://github.com/llvm/llvm-project/issues/97962#issuecomment-2213712656 I bisected the bug to that very commit. I'll try to add the reproducer tomorrow. 

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