Mutant failures caused by timeouts need to be more prominent

[dkubb]

When mutant fails because of a timeout violation it would be nice to have it more prominent. Especially when that failure results in a noop. I had some failures that seemed intermittent but it wasn't until @mbj pointed out the error logs that I could see there was a timeout error responsible for the noop.

My high level suggestion would be that there should be a summary of the failure as the very last thing printed to the screen before exiting. Then if I want more detail I can scroll up and dig in, but the summary would've been helpful in identifying the cause more early.