[clang] [clang][analyzer] Support 'getdelim' and 'getline' in StreamChecker (PR #78693)

[Balázs Kéri via cfe-commits]

balazske wrote:

I have already a working code to simplify code repetitions, but want to merge first patches #76979 and #78180 (@NagyDonat  could you look at these too?).

https://github.com/llvm/llvm-project/pull/78693