[clang] [clang][analyzer] Improve modeling of `fileno` in the StreamChecker (PR #76207)

[Ben Shi via cfe-commits]

benshi001 wrote:

`fileno` and `ftell` are quite similar, 

1. both of them return `0` on success, and `-1` on failure. 
2. both of them set `errno` on failure.

The differences are
1. `fileno` returns `int` type but `ftell` returns `long` type.
2. `ftell` will not affect the value of `error` on success, but this is not mentioned for `fileno`.

https://github.com/llvm/llvm-project/pull/76207