message: Add count / total column to BC profile
  Summary: Convenient.
diff: @@ -102,11 +102,18 @@ impl BcProfileData {
  .map(|(i, st)| (BcOpcode::by_number(i as u32).unwrap(), st))
  .collect();
  by_instr.sort_by_key(|(_opcode, st)| u64::MAX - st.count);
  - let mut csv = CsvWriter::new(["Opcode", "Count", "Total time (s)", "Avg time (ns)"]);
  let total: BcInstrStat = by_instr.iter().map(|(_opcode, st)| *st).sum();
  + let mut csv = CsvWriter::new([
  + "Opcode",
  + "Count",
  + "Count / Total",
  + "Total time (s)",
  + "Avg time (ns)",
  + ]);
  {
  csv.write_display("TOTAL");
  csv.write_value(total.count);
  + csv.write_display(format!("{:.3}", 1.0));
  csv.write_value(total.total_time);
  csv.write_value(total.avg_time().nanos);
  csv.finish_row();
  @@ -114,6 +121,10 @@ impl BcProfileData {
  for (opcode, instr_stats) in &by_instr {
  csv.write_debug(opcode);
  csv.write_value(instr_stats.count);
  + csv.write_display(format!(
  + "{:.3}",
  + instr_stats.count as f64 / total.count as f64
  + ));
  csv.write_value(instr_stats.total_time);
  csv.write_value(instr_stats.avg_time().nanos);
  csv.finish_row();
  