[clang] [analyzer] Avoid crashes in the stream checker (PR #100901)

[Balázs Kéri via cfe-commits]

balazske wrote:

> Exactly. I didn't want to rush too much, but I can share that my current idea is to call `assumeNoAliasingWithStdStreams` only on the success path.

This can be a better (and more simple) solution.

https://github.com/llvm/llvm-project/pull/100901