PCT-985 InnoDB Stats are not re-enabled after MySQL restart

The db name needs to be conditionalized. Yes "test_" is the normal prefix but it doesn't have to be. That aside for the moment, real problem is: `pct` db is not/should not be used for agent tests. For internal API tests this is normal, but agent cannot have any dependency like this because it's public code. If you need a db then use some temporary and probably unique like `percona_agent_test`.