[cpp] Bad code generation for class static references

```haxe
class Main {
static function main() {
final dist = MathLib.dist.between(2, 1);
trace(dist);
}
}

class MathLib {
public static final dist = Distance;
}

class Distance {
public static function between(x:Int, x2:Int):Int {
return x - x2;
}
}
```
```hxml
-cp src
-D analyzer-optimize
-main Main
--cpp bin/cpp
```
There is one cpp compilation error with `class Distance` and two if this class is `private`
```
Error: ./src/Main.cpp:35:40: error: no member named '_Main' in the global namespace; did you mean 'Main'?
35 | HXDLIN( 4) ::haxe::Log_obj::trace(::_Main::Distance_obj::between(2,1),::hx::SourceInfo(HX_("src/Main.hx",9a,7a,30,a1),4,HX_("Main",59,64,2f,33),HX_("main",39,38,56,48)));
| ~~^~~~~
```