Handle the upstream change to the previously broken draft 3 test.

Author: Julian

jsonschema/tests/test_jsonschema_test_suite.py

@@ -158,7 +158,6 @@ def leap_second(test):
         or skip(
             message=bug(),
             subject="ref",
-            valid=False,
             case_description=(
                 "$ref prevents a sibling id from changing the base uri"
             ),