DEG in N-Queen benchmark code for HP-42s

[rprosperi]

In calculations that don't depend on any angular mode, DEG is often used as a NOP, so that it has no effect. Note that in each case, DEG follows an ISG or DSE instruction, which in those cases are intended to not branch differently depending on on the outcome of the increment or decrement. Note that RAD or GRAD could also be used in the same way. Sometimes programs use X<>X instead, as this tends to be easier to figure out, but this could have undesirable small impacts on the stack or LASTX, so not always a good choice.