Add test for JPEG XL

Author: solonovamax

packages/core/integration-tests/test/integration/image/reformat-all.html

@@ -1,5 +1,6 @@
 ​<picture>
   <source srcset="foo.png?as=avif" type="image/avif">
+  <source srcset="foo.png?as=jxl" type="image/jxl">
   <source srcset="foo.png?as=jpg" type="image/jpeg">
   <source srcset="foo.png?as=png" type="image/png">
   <source srcset="foo.png?as=tiff" type="image/tiff">