Fix stale import: iris.allocators -> iris.host.memory.allocators

test_rocr_behaviors.py still referenced the old flat path for
VMemAllocator.

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

Author: mawad-amd

tests/unittests/test_rocr_behaviors.py

@@ -197,7 +197,7 @@ def test_vmem_allocator_uses_cumulative_access():
     """
     import torch.distributed as dist
 
-    from iris.allocators.vmem_allocator import VMemAllocator
+    from iris.host.memory.allocators.vmem_allocator import VMemAllocator
 
     rank = dist.get_rank()
     world_size = dist.get_world_size()