YARN-11290. Fix CheckStyle.

Author: slfan1989

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/test/java/org/apache/hadoop/yarn/server/router/clientrm/TestFederationClientInterceptor.java

@@ -28,12 +28,10 @@
 import java.util.Map;
 import java.util.HashMap;
 import java.util.Set;
-import java.util.function.Supplier;
 import java.util.stream.Collectors;
 import java.util.Arrays;
 
 import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
-import org.apache.hadoop.test.GenericTestUtils;
 import org.apache.hadoop.test.LambdaTestUtils;
 import org.apache.hadoop.util.Time;
 import org.apache.hadoop.yarn.MockApps;
@@ -134,7 +132,6 @@
 import org.apache.hadoop.yarn.server.resourcemanager.MockRM;
 import org.apache.hadoop.yarn.server.resourcemanager.MockNM;
 import org.apache.hadoop.yarn.server.resourcemanager.ResourceManager;
-import org.apache.hadoop.yarn.server.resourcemanager.reservation.Plan;
 import org.apache.hadoop.yarn.server.resourcemanager.reservation.ReservationSystem;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMApp;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMAppState;