Small simplication of see_ge()

[syzygy1]

Two simplifications:

• Remove the initialisation to 0 of occupied, which is now unnecessary.
• Remove the initial check for nextVictim == KING. If nextVictim == KING, then PieceValue[MG][nextVictim] will be 0, so that balance >= threshold is true. So see_ge() returns true anyway. To make this a bit more explicit, I have added corresponding initialisers to the PieceValue[][] array in psqt.c. (Interestingly, PSQT::init() already loops from W_PAWN to W_KING, so including the VALUE_ZERO values for W_KING seems to make sense for that reason alone.)

I don't think the later test in see_ge() for nextVictim == KING can be removed so easily, but I did not investigate thoroughly.

Running this on fishtest seem unnecessary, but let me know.

No functional change.

[mcostalba]

Merged with 741523e

I have removed the init part because redundant: global variables are zero initialized at startup (technically there is even no zero init involved, simply the OS maps process's global variables in a set of new memory pages that are ensured to be zero before to be mapped into user space).