Modify leaf related tests.

sharding-orchestration/sharding-orchestration-core/src/test/java/org/apache/shardingsphere/orchestration/internal/keygen/LeafSegmentKeyGeneratorTest.java

@@ -29,7 +29,6 @@ import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
-
 import static org.hamcrest.CoreMatchers.is;
 import static org.junit.Assert.assertThat;