Add SMT2 regression for minimize + define-fun-rec “canceled” failure

[Copilot]

A reported SMT2 optimization input using define-fun-rec and (minimize ...) was returning (error "...: canceled"), while an inlined equivalent did not. This change adds focused coverage for that exact shape so the behavior remains stable.

• Regression coverage

  • Added a new test case in src/test/smt2print_parse.cpp that evaluates the reported script through Z3_eval_smtlib2_string.
  • The test ensures this input is handled as a normal solver response (no parser/command error), matching current expected behavior.

• Test suite integration

  • Wired the new regression into tst_smt2print_parse() so it runs with existing SMT2 parse/eval regression coverage.

char const* spec =
    "(declare-const bound Int)\n"
    "(declare-const a Int)\n"
    "(declare-const b Int)\n"
    "(define-fun-rec f ((x Int) (y Int)) Bool ...)\n"
    "(assert ...)\n"
    "(minimize bound)\n"
    "(check-sat)\n";

test_eval(ctx, spec, false); // expect no error path