message: actually we should be safe always checking lower bound of billed_cpu_time_us in transaction_context::finalize(). (actual commit, ignore previous one)
diff: @@ -259,7 +259,7 @@ namespace eosio { namespace chain {
  billed_cpu_time_us = std::max( (now - pseudo_start).count(), static_cast<int64_t>(cfg.min_transaction_cpu_usage) );
  }
  - validate_cpu_usage_to_bill( billed_cpu_time_us, billed_cpu_time_us > 0 );
  + validate_cpu_usage_to_bill( billed_cpu_time_us );
  rl.add_transaction_usage( bill_to_accounts, static_cast<uint64_t>(billed_cpu_time_us), net_usage,
  block_timestamp_type(control.pending_block_time()).slot ); // Should never fail
  