[llvm] [CodeGen][Pass] Add `TargetPassBuilder` (PR #137290)

[Akshat Oke via llvm-commits]

optimisan wrote:

`injectBefore` and `disablePass` methods are independent of `addPass` calls which is nice.

But there are no virtual methods, so are we removing distinct phases (like `addPreEmitPasses()`) completely and only using `injectBefore()` now?
If we don't want overrides (virtual/CRTP) we could add "phase marker" passes (that are dummy passes like `ISelPrepareBegin()`) to be used with injectBefore.

https://github.com/llvm/llvm-project/pull/137290