Check-Minimal with Extra Tests is broken

Citus extension is left behind and dropping extension requires using DROP CASCADE

Ran: make install -j9 && make -C src/test/regress/ check-minimal EXTRA_TESTS='multi_extension'

Some errors found in diff file:
DROP EXTENSION citus;
+ERROR: cannot drop extension citus because other objects depend on it
+DETAIL: view columnar_test_helpers.chunk_group_consistency depends on table columnar.chunk
+HINT: Use DROP ... CASCADE to drop the dependent objects too.

CREATE EXTENSION citus VERSION '8.0-1';
+ERROR: extension "citus" already exists