Fix undefined behavior in search.

Fix undefined behavior in search.

We use following line to clamp the search depth in some range:
Depth d = std::clamp(newDepth - r, 1, newDepth + 1);

Through negative extension its possible that the maximum value becomes smaller than the minimum value but then the behavior is undefined (see https://en.cppreference.com/w/cpp/algorithm/clamp). So replace this line with a safe implementation.

Remark:
We have in recent master already one line where up to 3 negative extensions are possible which could trigger this undefined behavior but this can only be happen for completed depth > 24 so its not discovered by our default bench. Recent negative extension tests by @fauzi shows then this undefined behavior with wrong bench numbers.

closes https://github.com/official-stockfish/Stockfish/pull/4877

No functional change