Fix 1883

[jajhall]

fixColToLower and fixColToUpper merely had an assert if the lower or upper bound was infinite. Now, renamed fixColToLowerOrUnbounded and fixColToUpperOrUnbounded, they return true if the bound is infinite, in which case HPresolve::run() returns HighsPresolveStatus::kUnboundedOrInfeasible

This closes #1883