Remove mockedFunction for Node.js test runner mock fn

[fraxken]

Use the Node.js test runner mock.fn instead of the current mockedFunction (we dit that because mock was not available at the time).

js-x-ray/test/utils/index.js

Lines 9 to 27 in 5441439

	export function mockedFunction() {
	return {
	called: 0,
	args: [],
	at(position) {
	return this.args[position];
	},
	haveBeenCalledTimes(count = 0) {
	return this.called === count;
	},
	haveBeenCalledWith(value) {
	return this.args.includes(value);
	},
	callback(...args) {
	this.args.push(...args);
	this.called++;
	}
	};
	}