Normalize "pawn in front of minor" patch

No functional change.
Further tweak movecount pruning

Passed both short TC
LLR: 2.95 (-2.94,2.94)
Total: 15140 W: 3125 L: 2976 D: 9039

And long TC
LLR: 2.95 (-2.94,2.94)
Total: 17118 W: 3165 L: 2974 D: 10979

bench: 4132374
Further push singular extension

Extend for an extra half-ply in case the node is (probably)
going to fail high. In this case the added overhead is limited.

A novelity is the way this patch has been tested: Always in
self-play but with a much longer TC to allow the singular
extension to fully kick in and also (my impression) to have
less noisy results.

Ater 1015 games on my QUAD at 60"+0.05
Mod vs Orig 173 - 150 - 692 ELO +8
Revert "Further push singular extension"

This reverts commit dae6f9b8fc58763565e2ac46910f4db55e083189.

Failed on 60+0.05 with SPRT:

LLR: -2.97 (-2.94,2.94)
Total: 19045 W: 3409 L: 3417 D: 12219
Double impact of Gains table

It had already been tried and commited. Then it was reverted
based on regression tests result but its confidence level was
poor (below 90%), so check again with SPRT.
Merge branch '2.3.1_patches' of github.com:dorzechowski/Stockfish into 2.3.1_patches