Add test for numpy array alignment.

[robertnishihara]

This should be similar to https://github.com/apache/arrow/blob/23045d2b5be37df5cd990f5932576eb701e14b18/python/pyarrow/tests/test_serialization.py#L734-L754 except use ray.put and ray.get. E.g.,

for size in range(100):
    for dtype in [np.uint8, np.float32, np.float64, np.int64]:
        x = np.zeros(size, dtype=dtype)
        new_x = ray.get(ray.put(x))
        assert new_x.ctypes.data % 64 == 0