Host entity should be updated for revision changes

In field_collection_field_update(), the field collection gets saved. The host entity is only updated for "is_new" field collections, however, the host entity also needs to be set if the host's revision id has changed.
Currently, the any modules implementing hooks (hook_entity_update, etc) for field collection item entities do not have access to the host entity and entity type unless its explicitly set. The reason that they do not have access to the host entity is that the EFQ in fetchHostDetails() is executed for the new field collections revision id which has not been written to the field data tables for the host entity. The field tables are not updated until after field_collection_field_update has returned the new field collection ids.

Example call stack for a Commerce Order entity with a Field collection field.

• New order revision is triggered
  
  Order tables are updated with the new order revision.
  • Order's field_attach_update() is triggered.
    • Field collection: field_collection_field_update() fires
      • Triggers a new field collection revision via a save() with skipping the host entity save.
        • hook_entity_update for the field collection is triggered
          • Another contrib module (ie cer) attempts to get the field collection's hostEntity(), but fc's EFQ returns an empty result since fc revision id has not been updated in the field tables linking the fc revision to the host entity's new revision.
        • hook_entity_update for the field collection completed.
      • Field collection save completed.
    • Field collection: field_collection_field_update() returns fc's item id and new revision id
  • Order's field_attach_update() writes field data to field tables. Relationship between field collection and host updated - new field collection revision related to the new order revision.
• Order save completed.