gh-115119: Defer --with-system-libmpdec removal to 3.16
#205597
| Job | Run time |
|---|---|
| 4s | |
| 6s | |
| 10s |
--with-system-libmpdec removal to 3.16
#205597
| Job | Run time |
|---|---|
| 4s | |
| 6s | |
| 10s |