message: Purge old blocks from `exec_queue` when setting execution pre state
diff: @@ -654,6 +654,9 @@ impl ContractRuntime {
  let mut execution_pre_state = self.execution_pre_state.lock().unwrap();
  *execution_pre_state = sequential_block_state;
  + let mut exec_queue = self.exec_queue.lock().unwrap();
  + *exec_queue = exec_queue.split_off(&execution_pre_state.next_block_height);
  +
  // Initialize the system contract registry.
  //
  // This is assumed to always work. In case following query fails we assume that the node is
  