Memoize issuable counts in helper
This skips the AR query cache for issuable lists.
See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/14005/diffs#note_39231199.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
This skips the AR query cache for issuable lists.
See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/14005/diffs#note_39231199.