Avoid OOB for hi boundary planes

[mbkuhn]

Summary

With the previous fix for hi boundary planes, I corrected the indices of the face velocities but did not account for the fact that the plane data being referenced is still at cell centers. This PR accounts for that, supplying the IntVect to shift the indices back to cell-centered if needed. Augmented unit test to make sure it works.

Pull request type

• 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)
• 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