[llvm] [NewPM][CodeGen] add TargetPassConfig like API (PR #70906)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> Which part should run `MachineVerifier`? If in `MachinePassManager`, it can simplify the code in `CodeGenPassBuilder`. The `MachinePassManager` already has following codes:

Not sure I understand the question

> If in `CodeGenPassBuilder` then `llc` can support flags like `-stop-after=machineverifier,n`, and compatible with the old behavior.

What else would we do if not preserve this behavior?

https://github.com/llvm/llvm-project/pull/70906