EVM construct block

[sieniven]

Summary

• Pipeline to validate and execute transactions and update the new state into the block in finalize_block is shifted out into construct_block.
• Once the construction is done in a particular txqueue, the queue now holds the newly minted block in the queue.
• finalize_block will be called to commit the state and connect the block into storage. The old pipeline runs finalize_block twice (in ConnectBlock and subsequently in ConnectTip). This prevents redoing and running the block creation again.

Bug fixes

• Fix txqueue clear and drain_all methods bug to clear account nonce index.

Housekeeping

• Tidy up and add in description for evm tx validation pipeline.

Implications

• Storage

  • Database reindex required
  • Database reindex optional
  • Database reindex not required
  • None

• Consensus

  • Network upgrade required
  • Includes backward compatible changes
  • Includes consensus workarounds
  • Includes consensus refactors
  • None