Issue #3267274 by quietone, xjm, danflanagan8: Use aggregator fixture instead...
Issue #3267274 by quietone, xjm, danflanagan8: Use aggregator fixture instead of migrate_drupal fixture in d6/MigrateBlockTest
(cherry picked from commit 9bc2d73f6e3c25031b9ee998d0a28be55a86564f)