libcontainer/specconv: extend SetupSeccomp tests
libcontainer/specconv: extend SetupSeccomp tests

Extend the SetupSeccomp tests by adding the following cases:
- Test nil config
- Test empty config
- Test bad action and architecture
- Test all possible actions

Signed-off-by: Mauricio Vásquez <95f407c1ffa7689a0a3f2f21b1bf582fe8359351@kinvolk.io>

kolyshkin/runc,opencontainers/runc,opencontainers/runc,opencontainers/runc,kolyshkin/runc,rhatdan/runc,kolyshkin/runc,rhatdan/runc,rhatdan/runc,kolyshkin/runc,opencontainers/runc,rhatdan/runc