fix list.__add__ to use the expected type
#13529
| Job | Run time |
|---|---|
| 1m 22s | |
| 1m 12s | |
| 1m 13s | |
| 2m 5s | |
| 56s | |
| 1m 3s | |
| 1m 40s | |
| 1m 46s | |
| 1m 14s | |
| 43s | |
| 1m 2s | |
| 1m 57s | |
| 1m 1s | |
| 3m 34s | |
| 59s | |
| 1m 2s | |
| 2m 26s | |
| 41s | |
| 25m 56s |