Move tests to EXTRA_DIST
Move tests to EXTRA_DIST

As previously discussed, this is the intended use case for EXTRA_DIST
instead of treating the tests as dependencies of pick-test.

thoughtbot/pick,thoughtbot/pick,calleerlandsson/pick,calleerlandsson/pick,DBOTW/pick,DBOTW/pick,thoughtbot/pick,DBOTW/pick,calleerlandsson/pick,thoughtbot/pick