Optimize TranspositionTable::store() and TranspositionTable::probe() for...

... speed.

No functional change.

AMD Phenom II 3.6GHz, gcc 4.9.1, build ARCH=x86-64-modern
start /B /REALTIME /AFFINITY 0x1 stockfish.exe bench 1>nul

Master
4134
4118
4134
4134
4118

Patch
4025
4024
4009
4025
4009

Approximately 2.5% speedup