test: fix usage of old structural_simplify io syntax
#4198
| Job | Run time |
|---|---|
| 1m 4s | |
| 4s | |
| 1m 8s |
structural_simplify io syntax
#4198
| Job | Run time |
|---|---|
| 1m 4s | |
| 4s | |
| 1m 8s |