Prerender only render root document since 1.6.0

[DavidWiesner]

Stencil version:

 @stencil/core@1.6.1

I'm submitting a:

[x] bug report
[ ] feature request
[ ] support request => Please do not submit support requests here, use one of these channels: https://stencil-worldwide.herokuapp.com/ or https://forum.ionicframework.com/

Current behavior:
Prerender only render root document and failed to detect sub paths since @stencil/core@1.6.0

Expected behavior:
Prerender should detect and render all sub path recursively

Steps to reproduce:

One simple example is your stencil site repo.

1. clone repo stencil-site
2. install latest stencil core npm install @stencil/core@1.6.1
3. run npm run build
4. inspect www/sitemap.xml

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
 <url><loc>https://stenciljs.com/</loc></url>
</urlset>

5. install older version of stencil core npm install @stencil/core@1.6.1
6. run build again npm run build
7. inspect www/sitemap.xml

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
 <url><loc>https://stenciljs.com/</loc></url>
 <url><loc>https://stenciljs.com/blog</loc></url>
 <url><loc>https://stenciljs.com/design-systems</loc></url>
 <url><loc>https://stenciljs.com/resources</loc></url>
 <url><loc>https://stenciljs.com/blog/how-lazy-loading-web-components-work</loc></url>
 <!-- ... and many more -->

</urlset>

[pixelbucket-dev]

www/sitemap.xml still only has one route in latest stencil versions.