Optimize zip_findlast_entry and add benchmarks
#244
| Job | Run time |
|---|---|
| 4m 36s | |
| 3m 18s | |
| 6m 6s | |
| 4m 55s | |
| 6m 49s | |
| 5m 50s | |
| 8m 35s | |
| 7m 19s | |
| 5m 12s | |
| 3m 46s | |
| 7m 11s | |
| 10m 8s | |
| 4m 25s | |
| 5m 58s | |
| 1h 24m 8s |