Revert "Attempt fix for DynamicToyMySqlEntityTest int test"

This reverts commit ab1f99b8e26d5d9faa42400e387bcc4733d4c1c5.
Fix DynamicToyMySqlEntityTest intermittent fails

No need to background the server start command; it just makes things brittle if the server start takes more than 5 seconds (because that's when postStart checks that the service is running). Run it in foreground, and it will exit normally once the server is started.