[llvm] Changed stat passes to count instructions before and after optimizations (PR #188837)

[Arthur Eubanks via llvm-commits]

https://github.com/aeubanks commented:

I think "pre-optimization" makes more sense than "pre-passes", the important part is that we get the stats before any passes that actually optimize the IR are run. and the stats pass itself is a pass so it's a little weird

https://github.com/llvm/llvm-project/pull/188837