fix(fragmentArguments): arguments on directives for nested fields

Ports graphql-js 19b83f9f (#4180), a fixup to #4015: collect_subfields
did not thread the field's fragment_variables into the recursive
collect_fields_impl call, so directive arguments (@skip/@include) on
nested fields could not resolve fragment-scoped variables. The JS diff
also drops an unused fragmentVariableValues field from
CollectFieldsContext, which gc3's context never carried (N/A).

Author: Cito

src/graphql/execution/collect_fields.py

@@ -166,6 +166,7 @@ def collect_subfields(
                 sub_grouped_field_set,
                 new_defer_usages,
                 field_detail.defer_usage,
+                field_detail.fragment_variables,
             )
 
     return CollectedFields(sub_grouped_field_set, new_defer_usages)

tests/execution/test_variables.py

@@ -1324,6 +1324,19 @@ def when_argument_passed_to_a_directive():
             )
             assert result == ({}, None)
 
+        def when_argument_passed_to_a_directive_on_a_nested_field():
+            result = execute_query_with_fragment_arguments(
+                """
+                query {
+                  ...a(value: true)
+                }
+                fragment a($value: Boolean!) on TestType {
+                  nested { echo(input: "echo") @skip(if: $value) }
+                }
+                """
+            )
+            assert result == ({"nested": {}}, None)
+
     def describe_execute_uses_argument_default_values():
         def when_no_argument_provided():
             result = execute_query("{ fieldWithDefaultArgumentValue }")