octal: Ensure test versioning consistency with other exercises (#541)
octal: Ensure test versioning consistency with other exercises (#541)

* Relocated test versioning function to start of tests
* Errorf -> fatalf

See #470
exercism/xgo,robphoenix/exercism-go,leenipper/xgo,leenipper/xgo,robphoenix/exercism-go,exercism/xgo