Deprecation warnings in database_cleaner when MySQL is used
From https://gitlab.com/gitlab-org/gitlab-ee/-/jobs/190402936, we see these deprecation warnings:
DEPRECATION WARNING: #tables currently returns both tables and views. This behavior is deprecated and will be changed with Rails 5.1 to only return tables. Use #data_sources instead. (called from block (2 levels) in <top (required)> at /builds/gitlab-org/gitlab-ee/spec/support/database_cleaner.rb:29)
It's coming from this line: https://github.com/DatabaseCleaner/database_cleaner/blob/4c2408ffdbbd990e78d6590f4ef6ba5e58aca673/lib/database_cleaner/active_record/truncation.rb#L246