Fix mempool accounts view state mismatch

[sieniven]

Summary

• Remove accounts view rebuild pipeline on mempool reorg
• Add graceful fallbacks to create new block pipeline error failure - on first failure, mempool will do a rebuild of the accounts view state, and on second failure clear the mempool to prevent the miner from being stuck in a loop creating invalid blocks.

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