Add a new control message for destroying sandbox in multi-container mode.
Add a new control message for destroying sandbox in multi-container mode.

- Adds SandboxShutdown() control message to destroy sandbox manually.
- Adds a new gVisor API for destroying the sandbox in multi container mode.
- Test to verify the API and the control message works correctly.

PiperOrigin-RevId: 459290099

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