title: Doctrine json_array config wrong order in keys
body: <p>I have this weird problem with the json_array field configuration.</p>
  
  <p>I have configured field meant to store some configuration. Its configured like this:</p>
  
  <p><code>&lt;field name="config" type="json_array" /&gt;</code></p>
  
  <p>For example, I have an array like this:</p>
  
  <pre><code>[
      'choices' =&gt; [
          'Other' =&gt; 'other',
          'Male' =&gt; 'male',
          'Female' =&gt; 'female'
      ]
  ]
  </code></pre>
  
  <p>I set the entity property:</p>
  
  <pre><code>$entity-&gt;setConfig($config);
  </code></pre>
  
  <p>And I persist it to the database.
  The result is this:</p>
  
  <pre><code>"choices": {
      "Male": "male",
      "Other": "other", 
      "Female": "female"
  }
  </code></pre>
  
  <p>When I do json_encode on the same array, the order is not changed, but somehow Doctrine does change the order. Is there a way to prevent this from happening?</p>