Add `t.unorderedEqual()` assertion

[tommy-mitchell]

Closes #3020

Adds a new assertion for testing equality in an unordered manner between two Maps or two Sets/Arrays:

test('unorderedEqual', t => {
	t.unorderedEqual([1, 2, 3], new Set([2, 3, 1]));

	t.unorderedEqual(
		new Map([['a', 1], ['b', 2], ['c', 3]]),
		new Map([['b', 2], ['c', 3], ['a', 1]]),
		'Map keys should be equal!',
	);
});

---

Todos:

• Improve error messages, format values with concordance
• Improve types (e.g. Actual extends Map | Set | Array)
  • Add type tests
• Fix failing tests

[novemberborn]

Please re-open if you have a chance to return to this.

[tommy-mitchell]

@novemberborn I don't think I can reopen by myself.

[novemberborn]

I don't think I can reopen by myself.

@tommy-mitchell done!