Remove unnecessary thermo state call

[charleskawczynski]

One of our calls to saturation adjustment is unnecessary-- we call thermo_state! in explicit horizontal advection, after it's been computed in the implicit tendency function, so it can be removed. If we want to be able to swap the order of these calls (which some timesteppers may require), then we should either prescribe a flag to call them in a particular order, or a flag to indicate whether it's already been computed or not.

[charleskawczynski]

A flag for this is significantly easier without bycolumn calls

[charleskawczynski]

I think that this will be closed when #2015 is closed, so I'll close this now.