Use quiet ttMove in qsearch() (7962287)

Idea from Daniel Jose:
http://www.talkchess.com/forum/viewtopic.php?t=54290

**STC: Hash=16**

    LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
    Total: 33067 W: 6670 L: 6571 D: 19826

**LTC: Hash=64**

    LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
    Total: 41181 W: 7008 L: 6920 D: 27253

And another one to verify no regression with hash pressure:

**STC: Hash=4**

    LLR: 2.96 (-2.94,2.94) [-4.00,0.00]
    Total: 25085 W: 5059 L: 4991 D: 15035

There is a comment that claims this would trigger qsearch explosion with perpetual checks. But I doubt this because:
* of the QS recapture logic
* of the fact that perpet get pruned at the first repetition

If anyone can find an example of such a qsearch explosion, I am interested.

bench 7962287