[llvm] [NFC] Split portions of DWARFDataExtractor into new class (PR #140096)

[Paul Kirth via llvm-commits]

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

LGTM, since this is a straightforward refactoring. You may want to give code owners a chance to chime in before landing though.

https://github.com/llvm/llvm-project/pull/140096