Restrict mobility of pinned pieces

Passed both short TC:
LLR: 3.00 (-2.94,2.94) [-1.50,4.50]
Total: 54342 W: 10950 L: 10692 D: 32700

And long TC:
LLR: 2.95 (-2.94,2.94) [0.00,6.00]
Total: 61976 W: 10654 L: 10251 D: 41071

This patch introduces a slowdown of 3.5 % !!!!!

bench: 7911558
Revert "Retire eval margin and gains"

This reverts commit ecd07e51d0f03ccd3e41e5634518b299989254dd.

Patch was incorrect and partial. It will be reapplied in
the correct form.

bench: 9189063