Use the all matcher to check the existence of each path.

[alecclarke]

This change allows us to remove the RSpec/IteratedExpectation rule from .rubocop_todo.yml as we no longer iterate over each path to check existence.

Note: We this PR didn't change the subsequent test checking for the negative expectations as this isn't part of the rule (see: rubocop/rubocop-rspec#278).

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes? Here's an example.
• Have you successfully run brew style with your changes locally?
• Have you successfully run brew tests with your changes locally?

---

[reitermarkus]

Thanks, @alecclarke!