ALP-RD shouldn't require that right parts are non nullable

[robert3005]

Instead of forcing the callers to fill in the value we can fill in the nulls at decompression time.

[gatesn]

Does that mean both left and right parts can be nullable? That seems a little odd, given they're so intrinsically linked (i.e. you're not really going to process one half without the other). Contrast with dict encoding, where the values and codes are much more independent.