Instability in DataSourceTest: some test fixture orderings makes test_jdbc4_1 fail

If this test fixture is executed before the driver is loaded the first time, a call to EmbeddedDataSource40.getParentLogger will fail with this symptom:

org.apache.derby.impl.jdbc.EmbedSQLException cannot be cast to java.sql.SQLFeatureNotSupportedException

at org.apache.derby.jdbc.EmbeddedDataSource40.getParentLogger(EmbeddedDataSource40.java:193)
at org.apache.derbyTesting.functionTests.tests.jdbc4.Wrapper41DataSource.getParentLogger(Wrapper41DataSource.java:81)
at org.apache.derbyTesting.functionTests.tests.jdbc4.DataSourceTest.vetDSjdbc4_1(DataSourceTest.java:318)
at org.apache.derbyTesting.functionTests.tests.jdbc4.DataSourceTest.test_jdbc4_1(DataSourceTest.java:307)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at org.apache.derbyTesting.junit.BaseTestCase.runBare(BaseTestCase.java:117)
at org.apache.derbyTesting.junit.BaseJDBCTestCase.runBareOverridable(BaseJDBCTestCase.java:424)
at org.apache.derbyTesting.junit.BaseJDBCTestCase.runBare(BaseJDBCTestCase.java:441)