item_delete
item_delete(root, index);
assert(item_delete(&tree, 1000000));
assert(item_delete(&tree, 42));
assert(item_delete(&tree, i));
item_delete(&tree, tmp+1);
item_delete(tree, index);
item_delete(&tree, 1000000);
item_delete(&tree, 1000000);
ret = item_delete(tree, index);
ret = item_delete(tree, index);
ret = item_delete(tree, index);
item_delete(&tree, 1000000);
item_delete(&tree, 43);
int item_delete(struct radix_tree_root *root, unsigned long index);