Canister profiling (interim solution)

[chenyan-dfinity]

Current limitations:

• Logs are stored in the first page of stable memory (waiting for dedicated log memory)
  • breaks upgrade
  • traps if the log is too long
  • canister_init in Motoko cannot be profiled, because it uses stable_size to decide if there are stable vars to decode.
• Name section is exposed as active data segments in the first memory page, because passive data segments are not available. (waiting for the metadata endpoint)