gh-115119: Defer --with-system-libmpdec removal to 3.16
#205782
| Job | Run time |
|---|---|
| 5s | |
| 6s | |
| 11s |
--with-system-libmpdec removal to 3.16
#205782
| Job | Run time |
|---|---|
| 5s | |
| 6s | |
| 11s |