fetch support AbortSignal, zone.js schedules a macroTask when fetch()
```
fetch(..., {signal: abortSignal});
```
we should also be able to cancel fetch with `zoneTask.cancel` call.
So this commit create an internal AbortSignal to handle
`zoneTask.cancel()` call and also delegate the `options.signal` from the
user code.
PR Close#49595
Close#49591
```
const ac = new AbortController();
addEventListener(eventName, handler, {signal: ac.signal);`
ac.abort();
```
Currently `zone.js` doesn't support the `signal` option, this PR allows
the user to use AbortContoller to remove the event listener.
PR Close#49595
JiaLiPassion