windows-gnu: Adhere to MinGW convention for build outputs
#18609
| Job | Run time |
|---|---|
| 2h 24m 9s | |
| 2h 2m 37s | |
| 4h 53m 58s | |
| 3h 1m 18s | |
| 1h 24m 32s | |
| 1h 24m 32s | |
| 4h 31m 49s | |
| 2h 1m 27s | |
| 1h 23m 8s | |
| 28m 6s | |
| 23h 35m 36s |