Use pytest.warns instead of fixure filterwarning

This is better since it assers that warning is issues, and filters
it out, so test run of `test_sycl_device.py` is green, rather than
darker-yellow.

Author: oleksandr-pavlyk

dpctl/tests/_device_attributes_checks.py

@@ -90,9 +90,9 @@ def check_max_work_item_sizes3d(device):
         assert size is not None
 
 
-@pytest.mark.filterwarnings("DeprecationWarning:")
 def check_max_work_item_sizes(device):
-    max_work_item_sizes = device.max_work_item_sizes
+    with pytest.warns(DeprecationWarning):
+        max_work_item_sizes = device.max_work_item_sizes
     for size in max_work_item_sizes:
         assert size is not None