[clang] [analyzer] Do list initialization for CXXNewExpr with initializer list arg (PR #127702)

[Gábor Horváth via cfe-commits]

https://github.com/Xazax-hun approved this pull request.

This change looks good to me but the code makes me wonder if we correctly handle placement new.

What about cases like doing placement new into a non-zero'th element of a region like:
```
void f(S *a[]) {
  s[1] = new (S[1]) S{1, 2};
}
```

If this works as expected, that is great! If it does not, I am OK doing something about it in a follow-up PR. 

https://github.com/llvm/llvm-project/pull/127702