Fix a test helper

It should have been using xp.real(x) instead of x.real.

I'm not sure if float(x) or complex(x) would be better instead.

Author: asmeurer

array_api_tests/pytest_helpers.py

@@ -464,8 +464,8 @@ def assert_array_elements(
                 f"{sh.fmt_idx(out_repr, idx)}={at_out}, should be {at_expected} "
                 f"{f_func}"
             )
-            _assert_float_element(at_out.real, at_expected.real, msg)
-            _assert_float_element(at_out.imag, at_expected.imag, msg)
+            _assert_float_element(xp.real(at_out), xp.real(at_expected), msg)
+            _assert_float_element(xp.imag(at_out), xp.imag(at_expected), msg)
     else:
         assert xp.all(
             out == expected