Need to implement constituent code in updated SE dycore

### What is the feature/what would you like to discuss?

There are parts of the SE dycore in CAM-SIMA right now that were commented out before constituents infrastructure was in place.

Once #344 is brought in, as the constituents code is now available, they could be uncommented and ported to CAM-SIMA.

### Is there anyone in particular you want to be part of this conversation?

@nusbaume @PeterHjortLauritzen

### Will this change (regression test) answers?

Yes

### Will you be implementing this enhancement yourself?

No