[llvm] [llvm-dwp] Fix FoundCUUnit problem on soft-stop with DWARF5 (PR #169783)

[David Blaikie via llvm-commits]

dwblaikie wrote:

Please add test coverage, if possible. Or at least demonstrate hand-testing in the commit message? (I guess there's no nice way to test this without at least creating a 4GB test file during test execution?)

https://github.com/llvm/llvm-project/pull/169783