Firefox tests don't accurately depict duplicate requests (service worker)

[tkadlec]

When testing a site in Firefox where:

• a service worker exists
• the service worker requests a resource that either matches the main document, or has already been loaded by the main document

The waterfall incorrectly combines the two requests leading to some very weird waterfalls. Example, request 24 in the below waterfall for the main document.

[tkadlec]

Much better. :

)