[CI] Set test python.contrib.test_onnx.test_resize as xfail (#12568)

`python.contrib.test_onnx.test_resize` is failing due to a numerical
accuracy issue, reported in #12567. This patch marks that test as
an xfail, so that other tests can be enabled, while this one is
investigated separately.

tests/python/contrib/test_onnx.py

@@ -655,6 +655,7 @@ def verify_cast(dshape, dtype):
             verify_cast(i, o_dtype)
 
 
+@pytest.mark.xfail(reason="Known failing test. See issue #12567.")
 def test_resize():
     """Resize unit test."""