[clang] [analyzer] Add option assume-one-iteration (PR #125494)

[Balazs Benics via cfe-commits]

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

Reviewed the changes and it looks correct.
Please change the flag name (along with the comments to `assume-at-least-one-iteration`.

Please also review Edre's comments, those appear relevant.

https://github.com/llvm/llvm-project/pull/125494