[clang] [analyzer] Fix uninitialized base class with initializer list when ctor is not declared in the base class (#70464) (PR #70792)

[Balazs Benics via cfe-commits]

steakhal wrote:

> Do I need to
> 
>     * create a new PR?
> 
>     * push directly to this PR on the original branch `Snape3058:issue-70464`?
> 
>     * commit directly without revision?
> 
> 
> Which operation is correct?
> 
> (Sorry for not familiar with GitHub) -(

I'd prefer a new PR, and mentioning the original PR (the fix) and the issue for which it adds the test.

https://github.com/llvm/llvm-project/pull/70792