Shuffle movepicker score

Believed to be a speed optimization as benched
on Windows with bench realtime affinity 0x1 deleting
highest and lowest runs:

Base	Test
1549259	1608202
1538115	1583934
1543168	1556938
1536365	1554179
1533026	1582010

Signature remains unchanged and gives anywhere from 1-2% nps
boost in analysis depending on number of cores used.

No functional change.