[clang] [analyzer] Fix zext assertion failure in loop unrolling (PR #121203)

[Balazs Benics via cfe-commits]

steakhal wrote:

Could you please add a RUN line to the test, and a `// no-crash` comment at the line where previously crashed during interpretation?
I'd also prefer a `clang-formated` test file if possible.
Are you sure the test case is minimal and couldn't be minimized further now that you know why it crashes?

https://github.com/llvm/llvm-project/pull/121203