- Introduced `run_graphql_field` in tests that focus on resolving specific fields, leveraging the method added in GraphQL 2.2.0.
- Continued using `execute` for broader cases where it is still necessary to test entire GraphQL queries.
Back in commit c984e666f, we reorganized the code related to the GraphQL
API, but we didn't reorganize the tests.
So we're doing it now, since we're going to fix a potential issue and
add some tests for it.
