Remove as many feature = "std" gates in tests as possible
#503
| Job | Run time |
|---|---|
| 25s | |
| 20s | |
| 2s | |
| 10m 36s | |
| 2m 0s | |
| 9m 1s | |
| 2m 0s | |
| 21s | |
| 14s | |
| 3m 10s | |
| 42s | |
| 2m 3s | |
| 2m 4s | |
| 2m 32s | |
| 3s | |
| 35m 33s |