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

[Avi Kivity via llvm-commits]

avikivity wrote:

Thanks a lot @ellishg and @mtrofin for your help and guidance.

Can this please be backported to release/19.x?

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