Merge branch '42889-avoid-return-inside-block' of gitlab.com:jacopo-beschi/gitlab-ce into 42889-avoid-return-inside-block-ee

* '42889-avoid-return-inside-block' of gitlab.com:jacopo-beschi/gitlab-ce:
  Uses the rubocop helpers expect_offense and expect_no_offenses
  Updates after 4th review
  Updates after 3rd review
  Updates after 2nd review
  Fixes cop errors
  Adds AvoidBreakFromStrongMemoize Cop
  Minor review changes
  Adds Rubocop rule to avoid returning from a block