[clang] [analyzer] Model overflow builtins (PR #102602)

[Balazs Benics via cfe-commits]

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

Looks fantastic! I have no functional remarks. I only sprinkled it with some nits, but other than those it's perfect.
It's already good, I'll let you decide if you want to do the final touches or not as those may be more subjective suggestions.

https://github.com/llvm/llvm-project/pull/102602