Investigate cancun SELFDESTRUCT anomalies

[david-bakin-sl]

Reported questions about SELFDESTRUCT and BLOBBASEFEE (from test/examples in this repo).

Update: BLOBBASEFEE found to be an bug - issue #237

[david-bakin-sl]

See #16091 for BLOBBASEFEE issue. SELFDESTRUCT issue still being investigated.

[david-bakin-sl]

Issue reported for SELFDESTRUCT is that EIP-6780 clearly states that the target address for the sweep aka the beneficiary aka the obtainer (in our code for contract delete) can be the contract address itself and there are two cases:

• SELFDESTRUCT different transaction than contract created - this is the case where (post-cancun) the contract is not self destructed - contract keeps its balance
  • our behavior: return error SELF_DESTRUCT_TO_SELF - this is a bug as the contract/account is not deleted so it should work; in fact SELFDESTRUCT should work even if the account holds native (non-HBAR) tokens
• SELFDESTRUCT same transaction from contract created - this is the case where the contract is self destructed - "the Ether will be burnt"
  • our behavior: return SELF_DESTRUCT_TO_SELF - is this correct or not? do we have a way to burn HBAR? what happens if the contract account holds native tokens? Investigating this to see what the desired behavior is.

(The case of a HAPI ContractDelete call is that it always fails if there's a balance and the beneficiary is the contract account.)