Refactor AutoDevOps test to one test with two expectations

What does this MR do?

An attempt at making the auto devops spec a little bit more readable and maintainable.

Previously there were two specs inside of this file, both sharing the same before functionality, and very similar pipeline/job traversal.

This change consolidates these specs into one spec with what I hope is very little (if any) test time increase.

What are the relevant issue numbers?

• https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25782
• https://gitlab.com/gitlab-org/quality/nightly/issues/69
• https://gitlab.com/gitlab-org/quality/nightly/issues/71
• https://gitlab.com/gitlab-org/gitlab-ce/issues/57562

Does this MR meet the acceptance criteria?

• [-] Changelog entry added, if necessary
• [-] Documentation created/updated via this MR
• [-] Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• [-] Conforms to the database guides
• [-] Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• [-] Security reports checked/validated by reviewer