Per this discussion, create test fixtures for the finalized CID profile(s) and update the "Text fixtures" section in IPIP-499: ipfs/specs#499 (comment)

TODO

• implement kubo-* profile(s)
  • include CAR test fixtures for all UnixFS types (file, raw block, directory, HAMTdirectory)
  • adjust autosharding logic to do what JS does (based on full block size rather than just link names)
• deprecate test-* profiles