title: Missing @JsonTypeInfo property in serialized list with Jackson
body: <p>Jackson 2.9.2 allows to specify a property on a superclass to distinguish the type of subclasses with <code>JsonTypeInfo</code>, e.g.</p>
  
  <pre><code>@XmlRootElement
  @JsonTypeInfo(use = Id.CLASS,
                include = JsonTypeInfo.As.PROPERTY,
                property = "type")
  @JsonSubTypes({
      @Type(value = MyEntity.class)})
  @JsonIdentityInfo(
      generator = ObjectIdGenerators.PropertyGenerator.class,
      property = "id",
      scope=MySuperEntity.class)
  public class MySuperEntity {
      private Long id;
      private String myProperty;
  
      [0-arg constructor, (Long, String) contructor and getters and setters for both properties]
  }
  </code></pre>
  
  <p>A class <code>MyEntity</code> with extends <code>MySuperEntity</code> and adds on <code>String</code> property with getter and setter can be serialized with</p>
  
  <pre><code>ObjectMapper mapper = new ObjectMapper();
  long myEntityId = 1l;
  //test single
  MyEntity myEntity = new MyEntity(0,
          myEntityId,
          "");
  String expResultSingle = String.format("{\n" +
          "  \"type\" : \"richtercloud.jackson.type.in.list.MyEntity\",\n" +
          "  \"id\" : %d,\n" +
          "  \"myProperty\" : \"\",\n" +
          "  \"someProperty\" : 0\n" +
          "}",
          myEntityId);
  String result = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(myEntity);
  assertEquals(expResultSingle,
          result);
  </code></pre>
  
  <p>However when put into a <code>LinkedList</code> the generated JSON output doesn't have the <code>type</code> property:</p>
  
  <pre><code>//test list
  String expResultList = String.format("[ %s ]",
          expResultSingle);
  result = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(new LinkedList&lt;&gt;(Arrays.asList(myEntity)));
  assertEquals(expResultList,
          result);
  </code></pre>
  
  <p>fails due to</p>
  
  <pre><code>org.junit.ComparisonFailure: expected:&lt;[ {
    "[type" : "richtercloud.jackson.type.in.list.MyEntity",
    "]id" : 1,
    "myProper...&gt; but was:&lt;[ {
    "[]id" : 1,
    "myProper...&gt;
  </code></pre>
  
  <p>An SSCCE can be found at <a href="https://gitlab.com/krichter/jackson-type-in-list" rel="nofollow noreferrer">https://gitlab.com/krichter/jackson-type-in-list</a> with test output illustrating the issue at <a href="https://gitlab.com/krichter/jackson-type-in-list/-/jobs/55921526" rel="nofollow noreferrer">https://gitlab.com/krichter/jackson-type-in-list/-/jobs/55921526</a>.</p>