Don't log an error when stopping the container if it is not running.
Don't log an error when stopping the container if it is not running.

This removes a lot of confusing messages from the test logs.

PiperOrigin-RevId: 266164001

google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor