Avoid glacier dynamic landunit adjustments in first time step

[billsacks]

Description of changes

Always avoid generating dynamic landunit adjustments for glacier area changes in the first timestep of a startup or hybrid run - not just for cold start or interpolated start. See discussion in #340 for rationale.

Specific notes

Contributors other than yourself, if any: none

CTSM Issues Fixed (include github issue #):

• Fixes Avoid generating dynamic landunit adjustment fluxes for glacier changes in the first timestep #340

Are answers expected to change (and if so in what way)? YES

In general, can have answer changes in startup / hybrid tests that do not use init_interp, and use CISM (even NOEVOLVE), due to:

• different PE layout in new case vs. the one that generated the finidat (roundoff-level diffs)
• different glacier area on finidat file vs. what's in CISM (greater than roundoff-level diffs)

Any User Interface Changes (namelist or namelist defaults changes)? No

Testing performed, if any: Ran full aux_clm test suite

[billsacks]

@ekluzek I'm feeling like we really want to get this on master soon. What I'm not sure of is whether we want to bring this to the release branch. I did the same thing here as for the changes in my last tag: started a branch off of dev004 then merged in master before doing testing (so hopefully this makes things easier to bring this to the release branch if desired).

I'll talk to you, @dlawrenncar and @olyson about the question of whether this should go on the release branch on Wednesday. But if you get this message today and want to give me the go-ahead to bring it to master, I'll bring it to master today.

[ekluzek]

This is simple enough, so should be approved.

[ekluzek]

The one comment I have are about variables that predate this change. is_cold_start and is_interpolated_start. I'm wondering if instead of having several logical variables that have to be coordinated, if it should be a single variable that has a few valid options. Something like: start_type = 'COLD', 'INTERPOLATED', 'RESTART'.

But, that's a comment that essentially predates this PR, hence we should think about it as a clean-up step rather than a change here.