title: Custom font is not rendered to golden images when package is provided
body: <p>I have a custom font defined in module <code>theme</code>. This module is a dependency in module <code>widgets</code>. </p>
  
  <p>A widget in widgets module applies custom font like below</p>
  
  <pre><code>style: TextStyle(
    fontSize: fontSize,
    fontFamily: "IconActions",
    package: "theme"
  )
  </code></pre>
  
  <p>It works fine.</p>
  
  <p>Unfortunately this custom font is not rendered on golden images. I have to remove the <code>package: "theme"</code> to fix that. But that breaks the app and the font is not displayed any more.
  So basically I can have the font working correctly in the production code or the test code, but never both.</p>
  
  <p>The custom font is loaded in <code>setUp</code> method of the test</p>
  
  <pre><code>final fontData = File('assets/fonts/IconActions.ttf')
    .readAsBytes()
    .then((bytes) =&gt; ByteData.view(Uint8List.fromList(bytes).buffer));
  final fontLoader = FontLoader('IconActions')..addFont(fontData);
  await fontLoader.load();
  </code></pre>
  
  <p>Am I missing something, or is it a bug?</p>