Support chaining of map accessor [][] for each non-object in array

[northamerican]

These two tests describe the functionality:

test.skip('arr[].a[][] = x', t => {
    let arr = [{
        a: [10, 15]
    }, {
        a: [20, 25]
    }];

    arr[mapAccessorName].a[mapAccessorName][mapAccessorName] = 5;

    t.deepEqual(arr, [{
        a: [5, 5]
    }, {
        a: [5, 5]
    }]);
});

test.skip('arr[].a[][](n => x)', t => {
    let arr = [{
        a: [10, 15]
    }, {
        a: [20, 25]
    }];

    arr[mapAccessorName].a[mapAccessorName][mapAccessorName](n => n * 2);

    t.deepEqual(arr, [{
        a: [20, 30]
    }, {
        a: [40, 50]
    }]);
});