Fix test_all for cupy

Author: asmeurer

array_api_compat/cupy/_aliases.py

@@ -77,3 +77,5 @@
                               'acosh', 'asin', 'asinh', 'atan', 'atan2',
                               'atanh', 'bitwise_left_shift', 'bitwise_invert',
                               'bitwise_right_shift', 'concat', 'pow']
+
+_all_ignore = ['cp', 'get_xp']