title: Duplicate XML tags are not detected even when required properties are used
body: <p>I have a Springboot webservice application and I am using Jackson tags for XML and JSON. For JSON I am able to identify duplicates but not in XML.
  To detect duplicates in JSON following config is used</p>
  
  <pre><code>spring:
     jackson:
        deserialization:
           fail-on-unknown-properties: true
        parser:
           STRICT_DUPLICATE_DETECTION: true
  </code></pre>
  
  <p>DeserializationFeature.FAIL_ON_READING_DUP_TREE_KEY or JsonParser.Feature.STRICT_DUPLICATE_DETECTION none of them are working with XML input</p>
  
  <p>Config to detect duplicate is as given below</p>
  
  <pre><code>@Configuration
  public class AppConfig {
  
      @Bean(name = "xmlmapper")
      public ObjectMapper xmlObjectMapper() {
          ObjectMapper mapper = new XmlMapper();
          mapper.setSerializationInclusion(Include.NON_NULL);
          mapper.enable(DeserializationFeature.FAIL_ON_READING_DUP_TREE_KEY);
          mapper.enable(JsonParser.Feature.STRICT_DUPLICATE_DETECTION);
          return mapper;
      }
  }
  
  </code></pre>
  
  <p>Now when we give XML with duplicate element it is not throwing error by default it selects second tag value</p>
  
  <pre><code>&lt;Test&gt;
     &lt;A&gt;v1&lt;/A&gt;
     &lt;A&gt;v2&lt;/A&gt;
  &lt;/Test&gt;
  </code></pre>
  
  <p>Corresponding class is given below</p>
  
  <pre><code>@JacksonXmlRootElement(localName="Test")
  public class Test {
        @JsonProperty("A")
        @JacksonXmlProperty(localName="A")
        protected String a;
  }
  </code></pre>
  
  <p>Expected result is it should throw error when duplicate tags are passed in XML but it does not. I do not want to use case insensitivity as that would cause another issue.</p>