[debug] New thread detection removes stopped state

[thegecko]

If a new thread is detected, the known threads are updated.

As this new thread information no longer contains any stoppedDetails, if the debug is in a stopped state, this state is no longer reflected in the UI and instead looks like it is running.

This is because the stopped state is entirely dependent on the existence of stoppedDetails being added by the last thread update.

This issue is especially apparent during the startup stages in a slow debug adapter which has a breakpoint at it's point of entry. This is primarily due to the delay introduced by debouncing the thread calls.

Removing the debouncing fixes this issue in the case of the debug-cortex plugin, but this wouldn't fix a scenario when a new thread is started during debug.

I'm happy to open a PR to remove the debouncing, but would like opinions or other suggestions.

Thoughts @akosyakov @simark @marcdumais-work ?

[akosyakov]

stoppedDetails should be updated only by stop event, never by other clients