Prune ttMove like any other

No reason to treat the TT move differently. Prune it like any other and use `moveCount > 1` for LMR.

**STC with Hash=16**

    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 49264 W: 10076 L: 10007 D: 29181

**LTC with Hash=64**

    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 82149 W: 14044 L: 14023 D: 54082

Plus an extra test, to make sure it doesn't regress with strong hash pressure:

**STC with Hash=4**

    LLR: 2.95 (-2.94,2.94) [-4.00,0.00]
    Total: 21498 W: 4327 L: 4246 D: 12925

bench 7222112