The --no-watch flag doesn't work as expected

[azasypkin]

Summary

It seems when you use --no-watch flag (yarn start --no-watch) Kibana never reaches a state when user can interact with it. If you try to access Kibana the page will never load and in logs you'll see a notice from optimizer even though all bundles are ready and Kibana is fully booted.

please hold  optimizer is still bundling so requests have been paused
....
....
server    log   [09:01:34.773] [info][status] Kibana is now available (was degraded)

I admit that --no-watch in dev mode isn't that useful, but I found it handy while developing and testing Kibana interactive setup mode #89287. In this mode Kibana can write user configuration to kibana.yml while it is running. Since kibana.yml is being watched, any changes in it would trigger Kibana restart, and I'd like to avoid that.

// cc @spalger @thomheymann

[elasticmachine]

Pinging @elastic/kibana-operations (Team:Operations)