chg: ci: Revert "Workaround temporary cross-version-config-tests limitation"

With the release of BIND 9.19.25 this workaround is not needed anymore.

This reverts commit c58dd6e78f.

Merge branch 'mnowak/revert-workaround-temporary-cross-version-config-tests-limitation' into 'main'

See merge request isc-projects/bind9!9065

.gitlab-ci.yml

@@ -701,7 +701,6 @@ cross-version-config-tests:
     # Disable option checking to prevent problems with new default options in
     # the &configure anchor.
     EXTRA_CONFIGURE: "--disable-option-checking"
-    PYTEST: "/usr/bin/pytest-3"
   script:
     - *configure
     - *setup_interfaces
@@ -711,16 +710,13 @@ cross-version-config-tests:
     - autoreconf -fi
     - *configure
     - make -j${BUILD_PARALLEL_JOBS:-1}
+    - *find_pytest
     - cd bin/tests/system
     # Run the setup phase of all system tests in the most recently tagged BIND 9
     # release using the binaries built for the current BIND 9 version.  This
     # intends to detect obvious backward compatibility issues with the latter.
     - >
-      if [ -f isctest/vars/autoconf.py ]; then
-        echo "${CI_PROJECT_DIR}" > isctest/vars/.ac_vars/TOP_BUILDDIR
-      else
-        sed -i -E "s|(export TOP_BUILDDIR)=.*|\1=${CI_PROJECT_DIR}|" conf.sh;
-      fi
+      echo "${CI_PROJECT_DIR}" > isctest/vars/.ac_vars/TOP_BUILDDIR
     - >
       "$PYTEST" --setup-only --junit-xml="$CI_PROJECT_DIR"/junit.xml -n "${TEST_PARALLEL_JOBS:-1}"
   needs: