[clang] [llvm] [FlowSensitive] [StatusOr] [2/N] Add minimal model (PR #162932)

[Florian Mayer via cfe-commits]

fmayer wrote:

@Xazax-hun let me know whether you want me to wait for your review, or whether @jvoung's approval is enough. Thanks!

https://github.com/llvm/llvm-project/pull/162932