[clang] [clang] Add size filter for stack auto init (PR #74777)

[Vitaly Buka via cfe-commits]

vitalybuka wrote:

As we discussed offline, it would nice to handle cases like this
```
struct Foo {
    int x; // we should try to make sure X is initialized.
    char buff[1024];  // this one is fine to skip
};

void main() {
   Foo foo;
}
```

But seems moving size check deeper does not help. If so, simpler patch is preferred.

https://github.com/llvm/llvm-project/pull/74777