Update config_data_test
Update config_data_test

* Don't dot-import core_config
* Fix test pollution between marshal/unmarshal tests
* Add missing tests when unmarshal JSON is not ConfigVersion 3

markstgodard/cli,mcintyred/cli,cf-routing/cli,simonleung8/cli,markstgodard/cli,fujitsu-cf/cli,simonleung8/cli,cf-routing/cli,mcintyred/cli,hyenaspots/cli,mcintyred/cli,cf-routing/cli,mcintyred/cli,fujitsu-cf/cli,cf-routing/cli,simonleung8/cli,fujitsu-cf/cli,hyenaspots/cli,hyenaspots/cli,markstgodard/cli,hyenaspots/cli,markstgodard/cli