core, services: fix more import lints (#5021)

core/src/test/java/io/grpc/internal/RoundRobinLoadBalancerTest.java

@@ -624,6 +624,7 @@ public class RoundRobinLoadBalancerTest {
     picker = pickerCaptor.getValue();
 
     // second pick with a different stickiness value
+    @SuppressWarnings("unused")
     Subchannel sc2 = picker.pickSubchannel(mockArgs).getSubchannel();
 
     // go back to ready

core/src/test/java/io/grpc/util/ForwardingLoadBalancerTest.java

@@ -21,7 +21,6 @@ import static org.mockito.Mockito.mock;
 import io.grpc.ForwardingTestUtil;
 import io.grpc.LoadBalancer;
 import java.lang.reflect.Method;
-import java.net.SocketAddress;
 import java.util.Collections;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -41,7 +40,6 @@ public class ForwardingLoadBalancerTest {
 
   @Test
   public void allMethodsForwarded() throws Exception {
-    final SocketAddress mockAddr = mock(SocketAddress.class);
     ForwardingTestUtil.testMethodsForwarded(
         LoadBalancer.class,
         mockDelegate,

services/src/test/java/io/grpc/services/HealthCheckingLoadBalancerFactoryTest.java

@@ -71,6 +71,7 @@ import io.grpc.stub.StreamObserver;
 import java.net.SocketAddress;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.Deque;
 import java.util.HashMap;
 import java.util.LinkedList;
 import java.util.List;
@@ -959,9 +960,8 @@ public class HealthCheckingLoadBalancerFactoryTest {
   }
 
   private static class HealthImpl extends HealthGrpc.HealthImplBase {
-    boolean isImplemented = true;
     boolean checkCalled;
-    final LinkedList<ServerSideCall> calls = new LinkedList<ServerSideCall>();
+    final Deque<ServerSideCall> calls = new LinkedList<ServerSideCall>();
 
     @Override
     public void check(HealthCheckRequest request,