Change ENA ontology to ENA_test in populate.sql

`qiita_env make --load-ontologies` was broken because the populate-test-db.sql was inserting the ENA ontology, which was also in the ontologies file loaded from thebeast, which was causing constraint violations.  This changes the test ontology to have a different alias (`"ENA_test"`) and a different ID (`999999999`)
@ElDeveloper I just realized I forgot your comment here.  I'll add that.