Use git_clone_bind9-qa anchor in .system_test_common

This was missed in abecddb13a.

.gitlab-ci.yml

@@ -543,7 +543,7 @@ stages:
     - if pytest --version | grep -F "pytest 9.0" >/dev/null; then echo "filterwarnings = ignore::pytest.PytestRemovedIn9Warning" >> pytest.ini; fi
     - >
       ("$PYTEST" --junit-xml="$CI_PROJECT_DIR"/junit.xml -n "$TEST_PARALLEL_JOBS" | tee pytest.out.txt) || RET=1
-    - git clone --depth 1 https://gitlab.isc.org/isc-projects/bind9-qa.git
+    - *git_clone_bind9-qa
     - >
       "$PYTHON" bind9-qa/ci/postprocess_junit_files.py "$CI_PROJECT_DIR"/junit.xml --output "$CI_PROJECT_DIR"/junit.xml
     - (exit $RET)