assertEquals: no warnings or errors when used with WeakMap/WeakSet/WeakRef

[mfulton26]

none of the following throw an AssertionError:

assertEquals(new WeakMap([[a, 1]]), new WeakMap([[b, 2]]));
assertEquals(new WeakSet([a]), new WeakSet([b]));
assertEquals(new WeakRef(a), new WeakRef(b));

while each of the following do:

assertEquals(new WeakMap([[a, 1]]).get(a), new WeakMap([[b, 2]]).get(a));
assertEquals(new WeakSet([a]).has(a), new WeakSet([b]).has(a));
assertEquals(new WeakRef(a).deref(), new WeakRef(b).deref());

these seem like special cases where a deep equality assertion cannot be done; should some sort of warning and/or error be thrown instead of incorrectly asserting deep equality?

[kitsonk]

These should simply throw that they are uncomparable, as there is no way of deeply comparing them by their design.

[kt3k]

fixed by #951