[llvm] [NewPM][CodeGen] Let `ModuleToMachineFunctionPassAdaptor` own `MachineModuleInfo` (PR #87226)

[via llvm-commits]

paperchalice wrote:

> > `shared_ptr` seems better here.
> 
> Why? I generally think shared_ptr is not the answer

There might be several `<IR>ToMachineFunctionPassAdaptors` in pipeline, there is no benefit in considering ownership among these adapters, just let them share the `MachineModuleInfo`.

https://github.com/llvm/llvm-project/pull/87226