[clang] [Analyzer][CFG] Correctly handle rebuilt default arg and default init expression (PR #117437)

[via cfe-commits]

cor3ntin wrote:

I think `HasRebuiltInit` is just `CXXDefaultArgExpr::getExpr() != CXXDefaultArgExpr::getParam()->getDefaultArg()`

@yronglin Can you modify `hasRebuiltInit()` to be and see if anything breaks? (and if it works we don't need the bit)

```cpp
bool hasRebuiltInit() const { return getExpr() != getParam()->getDefaultArg(); }`
```

https://github.com/llvm/llvm-project/pull/117437