Double retries for rspec-retries

What does this MR do?

In https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/26934 we reduced retries from 2 * 4 to 1 * 2, which is causing unstable pipelines for us even after we quarantined fast.

This raises the retries from 1 * 2 to 1 * 4, which is doubling retries but still half from where it was.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• 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