QMetaType::NeedsConstruction does not check what it promises

QMetaType::NeedsContstruction promises that you can memset the type to zero for initialization. However, we set that flag when QTypeInfo<T>::isComplex is true. For Q_PRIMTIVE_TYPE, that flag is false; however primitive types don't give the guarantee that you can memzero them (see discussion https://lists.qt-project.org/pipermail/development/2020-November/040546.html), only that they can be memcpy'd.