Method destroyTree

src/fl/stl/detail/rbtree.h:241–248

    }

    void destroyTree(RBNode* node) {
        if (node != nullptr) {
            destroyTree(node->left);
            destroyTree(node->right);
            mAlloc.destroy(node);
            mAlloc.deallocate(node, 1);
        }
    }

    RBNode* copyTree(RBNode* node, RBNode* parent = nullptr) {
        if (node == nullptr) return nullptr;