Remove string_printable option from the solver

This is now done by Java object factory on inputs and others nondet
strings.
To add the constraint in other cases, this can be done using the
string_constrain_characters primitive.

Author: romainbrenguier

src/cbmc/cbmc_solvers.cpp

@@ -180,7 +180,6 @@ std::unique_ptr<cbmc_solverst::solvert> cbmc_solverst::get_string_refinement()
     info.string_max_length=options.get_signed_int_option("string-max-length");
   info.string_non_empty=options.get_bool_option("string-non-empty");
   info.trace=options.get_bool_option("trace");
-  info.string_printable=options.get_bool_option("string-printable");
   if(options.get_bool_option("max-node-refinement"))
     info.max_node_refinement=
       options.get_unsigned_int_option("max-node-refinement");

src/solvers/refinement/string_constraint_generator.h

@@ -42,8 +42,6 @@ class string_constraint_generatort final
   {
     /// Max length of non-deterministic strings
     size_t string_max_length=std::numeric_limits<size_t>::max();
-    /// Prefer printable characters in non-deterministic strings
-    bool string_printable=false;
   };
 
   string_constraint_generatort(const infot& info, const namespacet& ns);
@@ -347,7 +345,6 @@ class string_constraint_generatort final
   std::set<array_string_exprt> created_strings;
   unsigned symbol_count=0;
   const messaget message;
-  const bool force_printable_characters;
 
   std::vector<exprt> axioms;
   std::vector<symbol_exprt> boolean_symbols;

src/solvers/refinement/string_constraint_generator_main.cpp

@@ -31,7 +31,6 @@ string_constraint_generatort::string_constraint_generatort(
   const string_constraint_generatort::infot &info,
   const namespacet &ns)
   : max_string_length(info.string_max_length),
-    force_printable_characters(info.string_printable),
     ns(ns)
 {
 }