No longer leave this up to the test. All testing passes through the runTest() function, so we use that spot to delete the Realms. It also now deletes them beforehand too since a crash in a previous run could leave a Realm in place.
When deleteAll() is called on a Realm, it calls clear() on all of its Tables, which seems to not update TableViews unless they are synced. The is_row_attached(row_ndx) method still returns true otherwise. A workaround is here until that is fixed.
Fixes#434
Unfortunately, this was broken because our native Realm.Object constructor was not presenting itself as a function in JS. This fixes that and adds tests.
Turns out the JSC included with React Native on Android includes a buggy implementation of ArrayIterator that is missing an exposed next() method, so we implement it ourselves instead.