Fix NumberUtils min/max varargs dropping the sign of zero

[alhudz]

Repro: NumberUtils.max(-0.0d, 0.0d) returns -0.0 (so 1 / result is -Infinity); NumberUtils.min(0.0d, -0.0d) returns 0.0.

Cause: the double/float varargs overloads pick the extreme with </>, which rank -0.0 and 0.0 as equal, so the sign held in the accumulator survives. Math.max/Math.min, the three-argument min/max overloads and IEEE754rUtils all return the other sign for these inputs.

Fix: run the loop through Math.max/Math.min in the four double/float overloads, matching the three-argument versions. Those also propagate NaN, so the explicit isNaN check is no longer needed and the existing NaN results stay the same.