Perform prepare_boundaries at correct times

[mbkuhn]

Summary

Follow on to #1274 and fulfilling intention of #1210. Two changes:

1. fillphysbc calls at n+1/2 time to put time-correct values into nph variable states, which are already prepared to be used in advection. Without these calls (as it is after the no-diffs PR Set up prepare_boundaries as a step prior to ApplyPredictor #1274), the nph states are just the same as the old (n) states.
2. convert the usage of m_intended_interp_time to actually calculate the interpolation time. This is to interpolate the plane data at n+1/2 prior to the timestep and then at n+1 at the beginning of the timestep.

Pull request type

Please check the type of change introduced:

• 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

Additional background

Expected diffs are in the time-dependent BC cases (freestream_inout, rankine*) and the abl boundary input cases (abl_bndry_input*, abl_godunov_forcetimetable).

[mbkuhn]

something is off, failing asserts in ABLBoundaryPlane::populate_data

[mbkuhn]

with the latest rebase, no issues with time-based asserts

[marchdf]

The following tests FAILED:
          7 - abl_godunov_mpl (Failed)
          8 - abl_godunov_mpl_amr (Failed)
         75 - ow_linear_init_waves (Failed)
         88 - rankine (Failed)
         89 - rankine-sym (Failed)
         93 - freestream_godunov_inout (Failed)
        121 - abl_bndry_input_native (Failed)
        123 - abl_bndry_input_amr_native (Failed)
        124 - abl_bndry_input_amr_native_xhi (Failed)
        125 - abl_bndry_input_amr_native_mlbc (Failed)
        126 - abl_godunov_forcetimetable (Failed)
        127 - abl_bndry_input (Failed)
        128 - abl_bndry_input_amr (Failed)
        129 - abl_bndry_input_amr_inflow (Failed)
        130 - nrel_terrain (Failed)

Is that ok?

[mbkuhn]

yes. seems like a lot, but those are the expected diffs. (except for init_waves, of course, which is stuck on nans)