Do not use evaluate() for razoring

Because razoring is reached 10% of times and about 50% of time
first two conditions are met we can save 5% of calls to the fairly
costly evaluate().

On the other side statistics have shown 95% of nodes that pass
the first two razoring conditions pass also the evaluate() test.
So the risk of dropping the third condition seems low enough.

Testing seems to validate this.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/search.cpp

@@ -1122,9 +1122,7 @@ namespace {
         }
     }
     // Null move search not allowed, try razoring
-    else if (   depth < RazorDepth
+    else if (depth < RazorDepth && approximateEval < beta - RazorMargin)
-             && approximateEval < beta - RazorMargin
-             && evaluate(pos, ei, threadID) < beta - RazorMargin)
     {
         Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
         if (v < beta)