Fix test_all

Author: crusaderky

array_api_compat/cupy/_aliases.py

@@ -148,4 +148,6 @@ def take_along_axis(x: Array, indices: Array, /, *, axis: int = -1) -> Array:
                               'bool', 'concat', 'count_nonzero', 'pow', 'sign',
                               'take_along_axis']
 
-_all_ignore = ['cp', 'get_xp']
+
+def __dir__() -> list[str]:
+    return __all__