Test Easy Move if no BestMoveChanges

In case we find a very good move after a
troubled start, we don't return immediately
anymore.

Tested directly at long TC where it passed:
LLR: 2.95 (-2.94,2.94) [0.00,6.00]
Total: 13910 W: 2397 L: 2228 D: 9285

bench: 7995098
Merge branch 'master' of https://github.com/mcostalba/Stockfish into mcsyzygy