Fix reprocessing skipped jobs when retrying pipeline

What does this MR do?

This MR fixes a bug introduced in !9021 (merged) and makes it possible to reprocess jobs that we skipped after a failure in previous stages.

Does this MR meet the acceptance criteria?

• Tests added for this feature/bug

What are the relevant issue numbers?

See https://gitlab.com/gitlab-org/gitlab-ce/issues/26551#note_23929871