[llvm] [llvm-exegesis] Set stack pointer register after starting perf counter (PR #72489)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

@legrosbuffle Can you take another look at this? It should be ready and I think there's a compelling case for supporting user-set stack pointer registers.

https://github.com/llvm/llvm-project/pull/72489