Clean up tables after each test.

Follow-Up to https://github.com/rails/rails/pull/14400

This ensures that all tables are removed after each test and thereby
allowing us to run the tests in a random order.
Adding active_model in Rails::Info
Merge pull request #14463 from ankit8898/add_info

Adding active_model in Rails::Info
Merge pull request #14440 from tgxworld/mysql_table_cleanup_after_each_test

Clean up tables after each test.