Add synchronization points to triage non-reproducible test failure in CI

Author: oleksandr-pavlyk

dpctl/tests/test_usm_ndarray_manipulation.py

@@ -672,7 +672,9 @@ def test_roll_out_bounds_shifts():
 
     x_2d = dpt.reshape(x, (2, 2))
     y = dpt.roll(x_2d, np.uint64(2**63 + 1), axis=1)
+    y.sycl_queue.wait()
     expected = dpt.roll(x_2d, 1, axis=1)
+    expected.sycl_queue.wait()
     assert dpt.all(y == expected)
 
     x_2d_empty = x_2d[:, 1:1]