title: There is no user provider for user, symfony 3.4.37 and 4.4.3
body: <p>Since the upgrade to Symfony 3.4.37, I'm having this issue</p>
  
  <p>There is no user provider for user "Mybundle\Myuser".</p>
  
  <p>With version 3.4.36 and previous, it was working fine.</p>
  
  <p>security.yml</p>
  
  <pre><code>security:
    providers:
      myprovider:
          id: myuser.provider
  </code></pre>
  
  <p>services.yaml</p>
  
  <pre><code>myuser.provider:
      class: Mybundle\MyUserProvider
      public: true
      arguments: 
          - '@arg1'
      tags:
          - { name: monolog.logger, channel: app.oneid.provider }
  </code></pre>
  
  <p>Any idea on how to fix this issue?</p>
  
  <p>Edit: The support class of my user provider:</p>
  
  <pre><code>public function supportsClass($class)
  {
      return MyUserProvider::class === $class;
  }
  </code></pre>