Add E2E spec to ensure that issue closes with commit message

What does this MR do?

Closes gitlab-org/quality/testcases#15 (closed)

This MR adds new E2E spec to ensure that issue closes with commit message.

Here is a pipeline job with the new test passing: https://gitlab.com/gitlab-org/gitlab-ce/-/jobs/282473699

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry for user-facing changes, or community contribution. Check the link for other scenarios.
• [-] Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content