Incorrect directory structure in coverage reports

[tysmith]

For example:

GFX: ##.## % 
    Canvas: ##.## % 
        ImageBitmap: ##.## % 
    CSS Variable Font: ##.## % 
    WebGPU: ##.## % 
    WebAuthn: ##.## % 

WebAuthn should not be placed under GFX. Also the WR/webrender directory is missing completely.

[dveditz]

There's two parts of WebAuth. I think the listed line numbers line up with dom/webauthn, but there's also the authenticator-rs library. I don't know where these labels come from. If it's config script in the coverage tool then both of those could be combined as "webauthn" and assigned to the "crypto" top-level box.