hsd2nc does not work properly on non-S01 single-file inputs
Intent: write out an NC file for a single file instead of a whole scene. Fails because HimawariScene.shape returns the correct available shape, but the data is always copied from first line in the scene (not the file). This results in lots of fill values.
Solution should use line_offset properly for queries, and to clarify the difference between data shape and available extent.