Update the default `testGenerator` to avoid erroring on warnings.
Update the default `testGenerator` to avoid erroring on warnings.

This builds upon changes in broccoli-lint-eslint to add a third argument
that is the underlying ESLint results object. With this, we can
determine pass/fail based on `results.errorCount` (and not just the
presence of messages).  Using messages alone is not sufficient, because
it intermingles errors and warnings.

ember-cli/ember-cli-eslint,jonathanKingston/ember-cli-eslint,ember-cli/ember-cli-eslint,jonathanKingston/ember-cli-eslint