tests: add new task runner test helper
tests: add new task runner test helper

Adds a new helper and removes a duplicated test.

hashicorp/nomad,burdandrei/nomad,burdandrei/nomad,dvusboy/nomad,dvusboy/nomad,hashicorp/nomad,dvusboy/nomad,dvusboy/nomad,burdandrei/nomad,dvusboy/nomad,dvusboy/nomad,hashicorp/nomad,dvusboy/nomad,hashicorp/nomad,burdandrei/nomad,burdandrei/nomad,burdandrei/nomad,burdandrei/nomad,hashicorp/nomad,hashicorp/nomad