[clang] [clang][analyzer] Change default value of checker option in unix.StdCLibraryFunctions. (PR #80457)

[Balázs Kéri via cfe-commits]

balazske wrote:

Because the many cases with `fileno` I can agree to change the summary so we assume that it never fails. Probably an other checker may find a case if the passed file handle is invalid because it was not initialized, or the file was already closed (`StreamChecker` should find this).

https://github.com/llvm/llvm-project/pull/80457