Fix issue with free variables introduced by quantifier rewriter (#5602)

Fix issue with free variables introduced by quantifier rewriter (#5602)

This was caused by the quantifiers rewriting eliminating extended arithmetic operators, which was required due to the way counterexample-guided quantifier instantiation used to work with preprocessing. The technique is now more robust and this option can be deleted.

This fixes a debug assertion failure from UFNIA SMT-LIB, a minimized benchmark is included as a regression.