Update some older math routines

[cacraigucar]

Issue Type

Code Clean-up

Issue Description

A number of older math routines need updated code

The spreadsheet with the targetted code to be removed prior to CESM3 release is here: https://docs.google.com/spreadsheets/d/1kl5Csbt6QcKN5Uyf4kOSPOp7D5PI_kp1E_iMpS8p_A8/edit?gid=0#gid=0

@briandobbins has a branch with some log gamma fixes at this location:

Will this change answers?

I Don't Know

Will you be implementing this yourself?

Any CAM SE can do this

[cacraigucar]

@briandobbins - This may introduce roundoff level changes. Should it be done soon?

[briandobbins]

Yes, but it's still secondary to some of the science changes & tunings -- I gave Dave a heads-up on this a while back (eg, that we'd need time after the tuning is set), and will remind him again. Roundoff-level changes shouldn't impact the tuning.