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

[Avi Kivity via llvm-commits]

avikivity wrote:

btw, to reproduce the crash, build clang 18.1.6 with asan or stack protector. Without them, there's a buffer overflow that isn't detected. The reason I saw the problem is that Fedora's clang 18.1.6 is build with -fstack-protector-all.

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