* helper/resource: remove provider resolver test
* repl tests passing
* helper/resource: add some extra shimming to ShimLegacyState
Some of the tests in helper/resource have to shim between legacy and
modern states. Terraform expects modern states to have the Provider set
for each resource (and not be a legacy provider). This PR adds a wrapper
around terraform.ShimLegacyState which iterates through the resources
in the state (after the shim) and adds the provider FQN.