[llvm] [llvm-debuginfo-analyzer] Remove `LVScope::Children` container (PR #144750)

[Jakub Kuderski via llvm-commits]

https://github.com/kuhar requested changes to this pull request.

Please submit ADT changes in a separate PR to make it easy to revert. Would be also nice to add a unit test.

https://github.com/llvm/llvm-project/pull/144750