fix: handle empty /**/ in block_to_line assist
#40174
| Job | Run time |
|---|---|
| 5s | |
| 18s | |
| 8m 40s | |
| 47s | |
| 1m 26s | |
| 3m 54s | |
| 7m 22s | |
| 53s | |
| 5m 0s | |
| 1m 18s | |
| 5s | |
| 1m 15s | |
| 1m 58s | |
| 0s | |
| 2s | |
| 3s | |
| 33m 6s |
/**/ in block_to_line assist
#40174
| Job | Run time |
|---|---|
| 5s | |
| 18s | |
| 8m 40s | |
| 47s | |
| 1m 26s | |
| 3m 54s | |
| 7m 22s | |
| 53s | |
| 5m 0s | |
| 1m 18s | |
| 5s | |
| 1m 15s | |
| 1m 58s | |
| 0s | |
| 2s | |
| 3s | |
| 33m 6s |