[llvm] [llvm][AsmPrinter] Add an option to print instruction latencies (PR #113243)

[Jon Roelofs via llvm-commits]

jroelofs wrote:

> > [#113243 (review)](https://github.com/llvm/llvm-project/pull/113243#pullrequestreview-2384034868)
> 
> +1 on this
> 
> E.g., templatize the getLatency function on MachineInstr/MCInst and provide a functor to call `SubTargetInfo::resolveSchedClass`.

I am not sure where to put the common thing after adding overloads for that: `MCSchedModel` seems like the obvious place, but putting it there would be a layering violation, since it would cause `MC` to depend on `CodeGen`.

https://github.com/llvm/llvm-project/pull/113243