More RNG test fixes for MacOS

tests/integration/test_random_creation.py

@@ -72,7 +72,16 @@ def gen_random_from_both(
             # cuNumeric: keeps generating different arrays.
             # seed is respected in Eager mode.
         ),
-        None,
+        pytest.param(
+            None,
+            marks=pytest.mark.xfail(
+                not num.runtime.has_curand,
+                reason="legacy RNG fallback treats seed(None) as seed(0)",
+            ),
+            # https://github.com/nv-legate/cunumeric/issues/1018
+            # NumPy: seed(None) is equivalent to seed(<get_system_random>())
+            # cuNumeric non-cuRAND fallback: seed(None) equivalent to seed(0)
+        ),
         pytest.param(
             (4, 6, 8),
             marks=pytest.mark.xfail(
@@ -125,6 +134,10 @@ def test_default_rng_seed(seed):
     EAGER_TEST,
     reason="cuNumeric does not respect seed in Eager mode",
 )
+@pytest.mark.xfail(
+    not num.runtime.has_curand,
+    reason="XORWOW not available without cuRAND",
+)
 def test_default_rng_bitgenerator():
     seed = 12345
     rng_np_1 = np.random.default_rng(np.random.PCG64(seed))