cgen: fix type_default for option type when the default expr is none
#13145
| Job | Run time |
|---|---|
| 6m 15s | |
| 8m 42s | |
| 29s | |
| 36s | |
| 16m 2s |
none
#13145
| Job | Run time |
|---|---|
| 6m 15s | |
| 8m 42s | |
| 29s | |
| 36s | |
| 16m 2s |