Re-Add hashfull in last UCI info command using an approx value

[eduherminio]

• Add hashfull in last info command using an approx. value
  Aprox: non-default items in the first 1k TT entries

Context: hashfull uci info was removed in #342 due to having a serious perf. hit

6+0.06 [WIP]

Score of Lynx 1452 - hashfull approx vs Lynx 1447 - main: 4521 - 4571 - 3438  [0.498] 12530
...      Lynx 1452 - hashfull approx playing White: 2755 - 1812 - 1699  [0.575] 6266
...      Lynx 1452 - hashfull approx playing Black: 1766 - 2759 - 1739  [0.421] 6264
...      White vs Black: 5514 - 3578 - 3438  [0.577] 12530
Elo difference: -1.4 +/- 5.2, LOS: 30.0 %, DrawRatio: 27.4 %
SPRT: llr 0.797 (27.1%), lbound -2.94, ubound 2.94

end of it, before it got aborted:

   # PLAYER                         :  RATING  POINTS  PLAYED   (%)
   1 Lynx 1447 - main               :  2200.8  9582.5   19084    50
   2 Lynx 1452 - hashfull approx    :  2199.2  9501.5   19084    50

White advantage = 57.01
Draw rate (equal opponents) = 50.00 %

C:\dev\sprt>python3 sprt.py --wins 6927 --draws 5149 --losses 7008 --elo0 -5 --elo1 0
ELO: -1.47 +- 4.21 [-5.68, 2.73]
LLR: 0.846 [-5.0, 0.0] (-2.94, 2.94)
Continue Playing

8+0.08, results that can only be explained since 1452 is built with rc-1-

Finished game 6784 (Lynx 1447 - main vs Lynx 1452 - hashfull approx): * {No result}
Score of Lynx 1452 - hashfull approx vs Lynx 1447 - main: 2487 - 2388 - 1907  [0.507] 6782
...      Lynx 1452 - hashfull approx playing White: 1543 - 908 - 941  [0.594] 3392
...      Lynx 1452 - hashfull approx playing Black: 944 - 1480 - 966  [0.421] 3390
...      White vs Black: 3023 - 1852 - 1907  [0.586] 6782
Elo difference: 5.1 +/- 7.0, LOS: 92.2 %, DrawRatio: 28.1 %
SPRT: llr 2.96 (100.5%), lbound -2.94, ubound 2.94 - H1 was accepted