MULE-7673: DatabaseMuleArtifactTestCase broken after maven changes

There is a problem in the way JDBC functional tests manage Derby database. Apparently, problem occurs when the test shuts down the DB instance, killing the driver.
Starting/stopping MuleDerbyTestDatabase for this test fixes the problem
Merge pull request #793 from mulesoft/MULE-7673

MULE-7673: DatabaseMuleArtifactTestCase broken after maven changes