Fixing missing file in RegTests

[hgopalan]

Summary

This PR fixes the missing file in the RegTests

Pull request type

Please check the type of change introduced:

• [X ] Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

Checklist

The following is included:

• new unit-test(s)
• [X ] new regression test(s)
• documentation for new capability

This PR was tested by running:

• the unit tests
  • on GPU
  • on CPU
• the regression tests
  • on GPU
  • on CPU

Additional background

Issue Number:

[marchdf]

Awesome! Would you mind removing the png and then making sure that terrain_box test also has a terrain file?

[jrood-nrel]

I would recommend to rebase this PR so there aren't so many commits associated with this small change.