tests: Add non-power-of-2 shard shapes to benchmarks

Add (30,30,30) to large_morton_shards and (10,10,10), (20,20,20),
(30,30,30) to morton_iter_shapes to benchmark the scalar fallback path
for non-power-of-2 shapes, which are not fully covered by the vectorized
hypercube path.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: mkitti

tests/benchmarks/test_indexing.py

@@ -106,7 +106,8 @@ def read_with_cache_clear() -> None:
 
 # Benchmark with larger chunks_per_shard to make Morton order impact more visible
 large_morton_shards = (
-    (32,) * 3,  # With 1x1x1 chunks: 32x32x32 = 32768 chunks per shard
+    (32,) * 3,  # With 1x1x1 chunks: 32x32x32 = 32768 chunks per shard (power-of-2)
+    (30,) * 3,  # With 1x1x1 chunks: 30x30x30 = 27000 chunks per shard (non-power-of-2)
 )
 
 
@@ -197,9 +198,12 @@ def read_with_cache_clear() -> None:
 
 # Benchmark for morton_order_iter directly (no I/O)
 morton_iter_shapes = (
-    (8, 8, 8),  # 512 elements
-    (16, 16, 16),  # 4096 elements
-    (32, 32, 32),  # 32768 elements
+    (8, 8, 8),    # 512 elements    (power-of-2)
+    (10, 10, 10), # 1000 elements   (non-power-of-2)
+    (16, 16, 16), # 4096 elements   (power-of-2)
+    (20, 20, 20), # 8000 elements   (non-power-of-2)
+    (32, 32, 32), # 32768 elements  (power-of-2)
+    (30, 30, 30), # 27000 elements  (non-power-of-2)
 )