Harper should not warn about "too long JS execution" when using a debugger

[Ethan-Arrowood]

When using a debugger in application code, such as in a resources.js with jsResource. If you stay on the breakpoint for too long, the warn message:

[http/1] [warn]: JavaScript execution has taken too long and is not allowing proper event queue cycling, consider using 'await new Promise(setImmediate)' in code that will execute for a long duration

Will appear. This should not warn when the user is actively pausing execution intentionally.

We could just disable this message if threads.debug: true, or we can try to get fancier and see if there is something else we could detect (like if the user is actively using the debugger in that moment or not).

[kriszyp]

Hmm, yeah, I don't see anything in https://nodejs.org/dist/latest/docs/api/inspector.html that gives a hint to when a debugger is connected. And the problem with threads.debug is that it is basically always enabled for all our production/fabric instances (so this warning would never occur). Maybe this should be a separate configuration option that is disabled by default with the dev mode defaults.