TST: test that clip(x) returns a copy not a view

The spec only says that "If both min and max are None, the elements of
the returned array must equal the respective elements in x"

Bare NumPy 2.x and CuPy 13.x return copes:

>>> x = np.arange(8); np.may_share_memory(x, np.clip(x))
False

Thus assume that all wrapped libraries should return a copy, too.
Add a test to this effect.

Author: ev-br

tests/test_copies_or_views.py

@@ -62,3 +62,11 @@ def test_view_or_copy(inputs, xp_name):
     is_view_wrapped = is_view(wrapped_func, a1, value)
 
     assert is_view_bare == is_view_wrapped
+
+
+@pytest.mark.parametrize('xp_name', wrapped_libraries + ['array_api_strict'])
+def test_clip_none(xp_name):
+    xp = import_(xp_name, wrapper=True)
+
+    x = xp.arange(8)
+    assert not is_view(xp.clip, x, 42)