Reverse axes should follow reverse document order

[sadiqkhoja]

From the spec:

An axis is either a forward axis or a reverse axis. An axis that only ever contains the context node or nodes that are after the context node in document order is a forward axis. An axis that only ever contains the context node or nodes that are before the context node in document order is a reverse axis. Thus, the ancestor, ancestor-or-self, preceding, and preceding-sibling axes are reverse axes; all other axes are forward axes. Since the self axis always contains at most one node, it makes no difference whether it is a forward or reverse axis. The proximity position of a member of a node-set with respect to an axis is defined to be the position of the node in the node-set ordered in document order if the axis is a forward axis and ordered in reverse document order if the axis is a reverse axis. The first position is 1.

I expect following test to pass:

it.only('adhoc tests', () => {
	const testDocument = xml`
			<root>
			  <foo name="first">
			    <bar>Some content</bar>
			  </foo>
			</root>
`;
	const evaluator = new Evaluator({rootNode: testDocument});

	const actual = evaluator.evaluate(`//bar/ancestor::*[1]/@name`);

	expect(actual.stringValue).toBe('first');
})

In the current implementation //bar/ancestor::*[1] is selecting the root node, it should select foo node.