[Core]Fix ray.kill doesn't cancel pending actor bug (#14025)

java/test/src/main/java/io/ray/test/KillActorTest.java

@@ -59,6 +59,8 @@ public class KillActorTest extends BaseTest {
 
   private void testKillActor(BiConsumer<ActorHandle<?>, Boolean> kill, boolean noRestart) {
     ActorHandle<HangActor> actor = Ray.actor(HangActor::new).setMaxRestarts(1).remote();
+    // Wait for the actor to be created.
+    actor.task(HangActor::ping).remote().get();
     ObjectRef<Boolean> result = actor.task(HangActor::hang).remote();
     // The actor will hang in this task.
     Assert.assertEquals(0, Ray.wait(ImmutableList.of(result), 1, 500).getReady().size());