removeChild in BinaryTreeNode does not remove parent from child

[flurmbo]

Apologies if this is the expected behavior. In BinaryTreeNode.js, the function removeChild sets either this.left or this.right to null, but does not set nodeToRemove.parent to null. So for example the following test fails:

const rootNode = new BinarySearchTreeNode('foo');
rootNode.insert('bar');
const childNode = rootNode.find('bar');
rootNode.remove('bar');
expect(childNode.parent).toBeNull();

[trekhleb]

Thanks for noticing that @flurmbo . It is fixed now.