[clang] [clang][analyzer] Model more getline/getdelim pre and postconditions (PR #83027)

[Balázs Kéri via cfe-commits]

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

I did not find more issues (at least in `StreamChecker` and its tests). But did not check in detail the `UnixAPIChecker` part and tests.

https://github.com/llvm/llvm-project/pull/83027