fixup! Bug 31286: Implementation of bridge, proxy, and firewall settings in...

fixup! Bug 31286: Implementation of bridge, proxy, and firewall settings in about:preferences#connection

Bug 40843: Add a "testing" state to the internet status.

Bug 41383: Improved accessibility of the network status areas by
managing focus and making the status an aria-live area so that changes
are announced without requiring focus.

Also re-arranged the markup to ensure the "Connection" overview and
network status areas are not part of search results.

Also moved the "Tor network" status onto a new line:

1. This improved navigation with a screen reader.
2. Ensures that the "Tor network" status does not jump horizontally
   during a test.
3. Ensures that each status area does not take up too much horizontal
   space so that the minimum page width can reduce. E.g. the "Tor
   network" area regularly took up more than 50% of the available width,
   and these may be wider depending on the locale.