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

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 approved this pull request.

Also, now that there's been some discussion, we could probably rename `callbrprepare` (probably in a separate PR so this one can just land) as it's been added in the past ~two weeks and shouldn't be controversial to rename.

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