Preload render-delaying extensions

Shouldn't the following logic include the render-delaying extensions (`amp-experiment`, `amp-story`, `amp-dynamic-css-classes`) to add as preloads as well?

https://github.com/ampproject/amp-toolbox/blob/bf92d77fd1f53c54519bf8bed2be05b0bca26004/packages/optimizer/lib/transformers/RewriteAmpUrls.js#L174-L176

According to item 3. of the `Optimize your hosted AMP pages` guide:
> If your page includes render-delaying extensions (e.g., amp-experiment, amp-dynamic-css-classes, amp-story), preload those extensions as they're required by the AMP runtime for rendering the page.

Read packages/optimizer/lib/transformers/RewriteAmpUrls.js around the linked lines, then compare its preload handling with item 3 of the linked Optimize your hosted AMP pages guide. Verify whether amp-experiment, amp-story, and amp-dynamic-css-classes are included when present, and use the guide's required preload behavior as the completion check.

Written by the indexing model from the issue text.