[clang] [analyzer] Detect leak of a stack address through output arguments 2/3 (PR #105653)

[Donát Nagy via cfe-commits]

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

Looks good overall, but `getOriginRegion()` is a troublesome function (see inline comment for details).

https://github.com/llvm/llvm-project/pull/105653