Recycle failing language workers

Have seen a few scenarios where the functions host is running multiple language workers and some of them are consistently failing, while others are working fine. Often this involves some user code component going into a bad state.

In most cases this is resolved with a restart on the function app, but this is a heavy handed approach that requires manual intervention. The functions host should detect this scenario and attempt to resolve it by recycling the language workers that are failing. It will still be up to the user to analyze their logs and fix their problems, but the platform can reduce the impact until that happens by automatically recycling failing workers.

The single language worker case is a bit trickier. There's no obvious signal that a restart will fix the problem. I'd suggest the first version of this improvement should only kick in when there are multiple language workers.