validation: add a new test for NSPathMatchTypeError
validation: add a new test for NSPathMatchTypeError

`checkNSPathMatchType` checks if the container returns an error when
deliberately setting a wrong namespace type. Doing that, it is possible
to verify `NSPathMatchTypeError`, i.e. `The runtime MUST generate an
error if path is not associated with a namespace of type "type"`.

See also https://github.com/opencontainers/runtime-tools/issues/572

Signed-off-by: Dongsu Park <696fb7639d678a1e692fa501217d7509545d7331@kinvolk.io>

opencontainers/ocitools,opencontainers/ocitools,opencontainers/runtime-tools,opencontainers/runtime-tools