TST: Make use of clongdouble and longdouble

On some platforms float128 and complex256 do not exist.
Using (c)longdouble aliases should work on all platforms.

Author: bzah

numpy/lib/tests/test_function_base.py

@@ -2919,10 +2919,10 @@ def test_linear_nan_1D(self, dtype):
                       ] + [(np.float16, np.float64),
                            (np.float32, np.float64),
                            (np.float64, np.float64),
-                           (np.float128, np.float128),
+                           (np.longdouble, np.longdouble),
                            (np.complex64, np.complex128),
                            (np.complex128, np.complex128),
-                           (np.complex256, np.complex256),
+                           (np.clongdouble, np.clongdouble),
                            (np.dtype("O"), np.float64)]
 
     @pytest.mark.parametrize(["input_dtype", "expected_dtype"], H_F_TYPE_CODES)