[llvm] [CodeGen] Update DwarfEHPreparePass references in `CodeGenPassBuilder.h` and rename CallBrPrepare (PR #74068)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 commented:

`DwarfEHPrepare` updates LGTM. Meant to point that out yesterday.

I think we should drop the `CallBrPrepare` name change. There are a lot of legacy passes within LLVM that have been ported to the NewPM that never got renamed to legacy (including quite a few where I removed the legacy version recently). It's sort of just unnecessary churn in my opinion.

https://github.com/llvm/llvm-project/pull/74068