When a worker restarts we should clear all its errors in the error cache

[basarat]

The typescript worker has become a bit crashy lately. e.g. just right now :

To mitigate this we made the worker auto restarting with the right settings. But now the errors linger if it crashes.

Fix

Track all errors by their source in the error cache and allow us to clear errors by error source.

[basarat]

Released with 2.1.1 🌹