Fixed three broken tests.
Fixed three broken tests.

Three tests were broken by the move from `provider_state` to
`provider_states`. These needed to: 1) have the field name changed,
2) have the test itself adjusted for working with an iterator, and
3) one test needed to construct the `ProviderState` representing the
proper result of JSON processing.

pact-foundation/pact-reference,pact-foundation/pact-reference,pact-foundation/pact-reference,pact-foundation/pact-reference,pact-foundation/pact-reference,pact-foundation/pact-reference,pact-foundation/pact-reference,pact-foundation/pact-reference,pact-foundation/pact-mock-server