[llvm] [DebugInfo] Change return type of DWARFDebugAbbrev::parse (PR #67191)

[James Henderson via llvm-commits]

https://github.com/jh7370 commented:

In principle, seems reasonable to me, though I worry slightly about the impact on existing users who won't expect this breaking-if-they-have-appropriate-options-selected change. How confident are you that you've caught all in-tree uses?

Also, does this change allow us to check the lower-level error in a test somewhere, e.g. in a unit test?

https://github.com/llvm/llvm-project/pull/67191