Revert "Unroll prediction loop 4 times"
Revert "Unroll prediction loop 4 times"

It turned out not to help. These are times for the unrolled loop,
relative to the commit before:

| p10 | 1.013 ± 0.023 |
| p50 | 1.013 ± 0.019 |
| p90 | 0.996 ± 0.087 |
| μ   | 1.009 ± 0.029 |

No significant change there.

This reverts commit 73e9c3f510ba22c1677f568803bc41855693b45e.

ruuda/claxon,ruuda/claxon,ruuda/claxon