* command: refactor testBackendState to write states.State
testBackendState was using the older terraform.State format, which is no
longer sufficient for most tests since the state upgrader does not
encode provider FQNs automatically. Users will run `terraform
0.13upgrade` to update their state to include provider FQNs in
resources, but tests need to use the modern state format instead of
relying on the automatic upgrade.
* plan tests passing
* graph tests passing
* json packages test update
* command test updates
* update show test fixtures
* state show tests passing
James Bardin