[clang] [LifetimeSafety] Add missing origins stats for lifetime analysis (PR #166568)

[Utkarsh Saxena via cfe-commits]

https://github.com/usx95 requested changes to this pull request.

Awesome. This looks much better now.

One remaining concern I have is that we might be missing to record some missingOrigins here. Suggested a more black box collection style using RecursiveASTVisitor. Also it is important to not do this when `-print-stats`​ is disabled.

https://github.com/llvm/llvm-project/pull/166568