Fix malformed tests in test_usm_ndarray_dlpack

These tests would fail on machines with more than 2 devices for a given platform due to an incorrect asusmption that the DLPack device ID would match that of the cached root devices, of which only 2 are kept per platform

dpctl/tests/test_usm_ndarray_dlpack.py

@@ -84,7 +84,7 @@ def test_dlpack_device(usm_type, all_root_devices):
         assert type(dev) is tuple
         assert len(dev) == 2
         assert dev[0] == device_oneAPI
-        assert sycl_dev == all_root_devices[dev[1]]
+        assert dev[1] == sycl_dev.get_device_id()
 
 
 def test_dlpack_exporter(typestr, usm_type, all_root_devices):
@@ -834,15 +834,15 @@ def test_sycl_device_to_dldevice(all_root_devices):
         assert type(dev) is tuple
         assert len(dev) == 2
         assert dev[0] == device_oneAPI
-        assert dev[1] == all_root_devices.index(sycl_dev)
+        assert dev[1] == sycl_dev.get_device_id()
 
 
 def test_dldevice_to_sycl_device(all_root_devices):
     for sycl_dev in all_root_devices:
         dldev = dpt.empty(0, device=sycl_dev).__dlpack_device__()
         dev = dpt.dldevice_to_sycl_device(dldev)
         assert type(dev) is dpctl.SyclDevice
-        assert dev == all_root_devices[dldev[1]]
+        assert dev.get_device_id() == sycl_dev.get_device_id()
 
 
 def test_dldevice_conversion_arg_validation():