Fix undefined behavior in search.

[locutus2]

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 save 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.

Bench: 1334248

[Disservin]

The comment is a bit long for my taste. Maybe smth like To prevent problems when the max value is less than the min value, swapped std::clamp for a safer implementation.

[locutus2]

@Disservin
On contrare, the commit should explain context. It was always our wish to give more then less information in the commit.

[Disservin]

I have no problem with a detailed explanation in the commit. However the comment in the code should be short and precise, not tell a story.