- Pass status code to cancelled TRR channels
- When TRR timer expires, use NS_ERROR_NET_TIMEOUT_EXTERNAL
- When TRR is cancelled by nsHostResolver use NS_ERROR_ABORT
- Only call TRRIsOkay in OnStopRequest (doing so in TRR::Cancel causes us to
call it twice for the same TRR)
- Use NS_NewRunnableFunction instead of ProxyCancel runnable object
- Introduce TRR_REQ_CANCELLED skip reason
Differential Revision: https://phabricator.services.mozilla.com/D104371