Add portable-atomic crate for the platforms where AtomicU64 is not available
#2002
| Job | Run time |
|---|---|
| 3s | |
| 3m 58s | |
| 3m 15s | |
| 3m 54s | |
| 7m 23s | |
| 4m 35s | |
| 4m 29s | |
| 27m 37s |