No Ply Restriction in the condition that limits the depth extension t…

…o a certain point

No Ply Restriction in the condition that limits the depth extension to a
certain point.

Passed again LTC rebased:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 195108 W: 49916 L: 49872 D: 95320
Ptnml(0-2): 170, 21846, 53464, 21918, 156
https://tests.stockfishchess.org/tests/view/6795542a406a4efe9eb7d361

closes #5824

Bench: 1767398

src/search.cpp

@@ -1239,7 +1239,7 @@ Value Search::Worker::search(
             (ss + 1)->pv[0] = Move::none();
 
             // Extend move from transposition table if we are about to dive into qsearch.
-            if (move == ttData.move && ss->ply <= thisThread->rootDepth * 2)
+            if (move == ttData.move && thisThread->rootDepth > 8)
                 newDepth = std::max(newDepth, 1);
 
             value = -search<PV>(pos, ss + 1, -beta, -alpha, newDepth, false);