Parameter tweak from various tunes and patches.

STC https://tests.stockfishchess.org/tests/view/5fec2ae36019e097de3ee94a
LLR: 2.97 (-2.94,2.94) {-0.25,1.25}
Total: 41976 W: 4032 L: 3848 D: 34096
Ptnml(0-2): 147, 3086, 14341, 3264, 150

LTC https://tests.stockfishchess.org/tests/view/5fec5c3c6019e097de3ee973
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 23936 W: 970 L: 844 D: 22122
Ptnml(0-2): 14, 749, 10319, 869, 17

closes official-stockfish#3281

bench: 4354546

Late irreversible move extension seems to be useless now.

STC https://tests.stockfishchess.org/tests/view/5fe75c5c3932f79192d398ca
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 196192 W: 18111 L: 18278 D: 159803
Ptnml(0-2): 681, 14097, 68652, 14040, 626

LTC https://tests.stockfishchess.org/tests/view/5fe875e23932f79192d39952
LLR: 2.96 (-2.94,2.94) {-0.75,0.25}
Total: 28080 W: 1105 L: 1053 D: 25922
Ptnml(0-2): 13, 904, 12158, 948, 17

closes official-stockfish#3279

bench: 4144640

has become ineffective now.

STC https://tests.stockfishchess.org/tests/view/5fe653403932f79192d3981a
LLR: 2.95 (-2.94,2.94) {-1.25,0.25}
Total: 63448 W: 5965 L: 5934 D: 51549
Ptnml(0-2): 230, 4738, 21769, 4745, 242

LTC https://tests.stockfishchess.org/tests/view/5fe6f0f03932f79192d39856
LLR: 2.93 (-2.94,2.94) {-0.75,0.25}
Total: 65368 W: 2485 L: 2459 D: 60424
Ptnml(0-2): 33, 2186, 28230, 2192, 43

closes official-stockfish#3278

bench: 4493379

Do not give the WeakUnopposed penalty for backwards on file A or H

The original idea comes from Lolligerhans, and a series of tunings and tests done by Fauzi.

Passed STC:
LLR: 2.96 (-2.94,2.94) {-0.25,1.25}
Total: 140864 W: 28127 L: 27660 D: 85077
Ptnml(0-2): 2529, 16660, 31735, 16831, 2677
https://tests.stockfishchess.org/tests/view/5fe39dec3932f79192d39673

Passed LTC:
LLR: 2.95 (-2.94,2.94) {0.25,1.25}
Total: 67568 W: 8993 L: 8590 D: 49985
Ptnml(0-2): 523, 6176, 19983, 6579, 523
https://tests.stockfishchess.org/tests/view/5fe3dd1b3932f79192d39693

closes official-stockfish#3275

Bench: 4109336