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

[via llvm-commits]

paperchalice wrote:

Which part should run `MachineVerifier`? If in `MachinePassManager`, it can simplify the code in `CodeGenPassBuilder`.
The `MachinePassManager` already has following codes:
https://github.com/llvm/llvm-project/blob/fd8be1ef598da48897f396296c03a576bf391378/llvm/lib/CodeGen/MachinePassManager.cpp#L37-L50
If in `CodeGenPassBuilder` then `llc` can support flags like `-stop-after=machineverifier,n`, and compatible with the old behavior.


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