4.6's 3 empties search order is different from 4.4 and 4.5

[okuhara]

The search_solve_3 in the 4.4 sorts 3 empties in the search->empties, while the solve_3 in the 4.6 sorts x1, x2 and x3 parameters, those are reordered in the search_solve_4. This does not affect final score but results in slightly worse searched nodes.
The 4.5 also uses reordered x1, x2 and x3 so compensate that in the sort3 parameter.

[abulmo]

It's hard to measure the effect on my computers. Whatever, I modified the code to reorder the move based on square type, but I want to do other changes before a release.