Clean up uses of is_primitive_wrapper_type_name that derive the name from a symbol-table id

These users start with an irep_idt, so it's cheaper to look up by id than to create a derived
string and then look up by that.

Author: smowton

jbmc/src/java_bytecode/assignments_from_json.cpp

@@ -543,9 +543,7 @@ static code_with_references_listt assign_struct_components_from_json(
     else // component is class field (pointer to struct)
     {
       const auto member_json = [&]() -> jsont {
-        if(
-          is_primitive_wrapper_type_name(id2string(
-            strip_java_namespace_prefix(java_class_type.get_name()))) &&
+        if(is_primitive_wrapper_type_id(java_class_type.get_name()) &&
           id2string(component_name) == "value")
         {
           return get_untyped_primitive(json);

jbmc/src/java_bytecode/java_utils.cpp

@@ -104,6 +104,10 @@ get_java_primitive_type_info(const typet &maybe_primitive_type)
   return found == type_info_by_primitive_type.end() ? nullptr : &found->second;
 }
 
+bool is_primitive_wrapper_type_id(const irep_idt &id) {
+  return  get_boxed_type_info_by_name(id) != nullptr;
+}
+
 bool is_primitive_wrapper_type_name(const std::string &type_name)
 {
   static const std::unordered_set<std::string> primitive_wrapper_type_names = {

jbmc/src/java_bytecode/java_utils.h

@@ -62,8 +62,12 @@ struct java_boxed_type_infot
 const java_boxed_type_infot *
 get_boxed_type_info_by_name(const irep_idt &type_name);
 
+/// Returns true iff the argument is the symbol-table identifier of a Java
+/// primitive wrapper type (for example, java::java.lang.Byte)
+bool is_primitive_wrapper_type_id(const irep_idt &id);
+
 /// Returns true iff the argument is the fully qualified name of a Java
-/// primitive wrapper type.
+/// primitive wrapper type (for example, java.lang.Byte)
 bool is_primitive_wrapper_type_name(const std::string &type_name);
 
 void generate_class_stub(