[GCP] Make tpu an opt-in option in the backend configuration
#6510
| Job | Run time |
|---|---|
| 3s | |
| 1m 15s | |
| 43s | |
| 1m 9s | |
| 10s | |
| 54s | |
| 8s | |
| 19s | |
| 19s | |
| 4m 12s | |
| 2m 44s | |
| 4m 12s | |
| 2m 32s | |
| 6m 3s | |
| 5m 30s | |
| 4m 30s | |
| 3m 33s | |
| 2m 59s | |
| 2m 11s | |
| 2m 11s | |
| 6m 5s | |
| 2m 13s | |
| 5m 24s | |
| 6m 7s | |
| 32s | |
| 34s | |
| 20s | |
| 15s | |
| 1h 7m 7s |