[Tests] Add evaluator tests to make sure static evaluation scores relative to sidetomove

[KYLChiu]

NB: static evaluation function must return a score relative to the side to being evaluated, e.g. the simplest score evaluation could be:
score = materialWeight * (numWhitePieces - numBlackPieces) * who2move

• positive if winning and if on side to move,
• negative if winning and not on side to move