Invoke webpacker compile/clobber tasks for tests
Invoke webpacker compile/clobber tasks for tests

Lazy compilation for Webpacker does not appear to work well when
executing tests from outside the sample app directory so we invoke them
eagerly from Rake.

rossta/serviceworker-rails,rossta/serviceworker-rails,rossta/serviceworker-rails,rossta/serviceworker-rails