Add test for conservation of kinetic energy with topography

[dennisYatunin]

Purpose

This PR adds a test for exact conservation of kinetic energy in the presence of topography. The test currently passes with the changes from #2960, and it would be helpful to see whether it passes without those changes.

To-do

Update the relevant Jacobian terms, and add a test that uses implicit timestepping.

---

• I have read and checked the items on the review checklist.

[szy21]

Do you need to change something in the Jacobian as well?

[dennisYatunin]

Yes, I need to turn off gravity and pressure gradients in the vertical velocity tendency derivatives