Migrate current callers to level-indexed refinement API

tests/validation/multigrid/test_refinement_blocked_fine.py

@@ -125,7 +125,7 @@ class BlockedFineCPU(unittest.TestCase):
                 patch.object(cuda, "mem_alloc", side_effect=alloc), patch.object(cuda, "memcpy_htod"):
             backend = FixedPatchStepper(config("periodic"), context=context, refinements=[BOUNDS],
                                         level_blocks=[(12, 8), FINE_BLOCKS[0]])
-            self.assertEqual(len(backend.fine_layout.halo_dst), 0)
+            self.assertEqual(len(backend.layouts[1].halo_dst), 0)
             self.assertIsNone(backend._levels[1].halo_dst)
             backend._gather_halo(backend._levels[1], Mock())  # no launch without pairs
             module.get_function.return_value.assert_not_called()
@@ -178,7 +178,7 @@ class BlockedFineCPU(unittest.TestCase):
             backend = FixedPatchStepper(config("periodic"), context=context, refinements=[BOUNDS],
                                         level_blocks=[(12, 8), FINE_BLOCKS[1]],
                                         level_objects=[(), tuple(objects)])
-            backend.initialize(state(NY, NX, 1), state(*backend.patch.fine_shape, 2))
+            backend.initialize(state(NY, NX, 1), state(*backend.hierarchy.pairs[0].fine_shape, 2))
         return backend, calls
 
     def test_same_buffer_halo_bfl_step_launch_order(self):
@@ -212,7 +212,7 @@ class BlockedFineCPU(unittest.TestCase):
     def test_actuation_without_velocity_buffer_fails_before_bfl(self):
         for speed in (0.0, .002):  # any spec, even zero amplitude
             backend, calls = self.mocked_backend([circle(actuation(speed))])
-            self.assertIsNotNone(backend._fine_tables["surface_velocity"])
+            self.assertIsNotNone(backend._level_boundaries[1].tables["surface_velocity"])
             del backend._level_boundaries[1].device["surface_velocity"]
             with self.assertRaisesRegex(RuntimeError, "Surface velocity device buffer is missing"):
                 backend.step(1)