Fix reduction order in Nock spec

The way one is supposed to use the Nock spec is by repeatedly going through the reduction rules from top to bottom, and applying the first rule that matches. Some rules (for ```10``` and ```+```) appear to be in the wrong order: a more general rule is above a more specific rule, making the latter unreachable. It looks like this kind of issue has been around since Nock 8K.

To illustrate, I've modified the 5K spec. Perhaps that's heretical, though! Let me know if I should have proposed a 4K spec, or done something else.