Remove Unconditional time out wait for diagnostic. See `expectNoMoreDiagnostics`

It it not an easy job to remove this one. There are multiple states we need to monitor to wait for hls to settle.
After discussion with @michaelpj , we can replace the `expectNoMoreDiagnostics`'s time out with following:

* restartQueue empty
* actionQueue empty
* sessionLoader Queue empty
* rebouncer done
* hls-graph database all running is done

What we need to do:

* [x] #4301
* [ ] #4309
* [ ] implement `rebouncer` done utility.
* [ ] refactor the test util to make use of the above.