JBMC: don't recompute class hierarchy per function

We already have a class_hierarchyt for use with other classes, just pass it in to avoid
pointless recomputation.

Author: smowton

jbmc/src/jbmc/jbmc_parse_options.cpp

@@ -753,7 +753,7 @@ void jbmc_parse_optionst::process_goto_function(
     *class_hierarchy,
     ui_message_handler);
   // Java virtual functions -> explicit dispatch tables:
-  remove_virtual_functions(function);
+  remove_virtual_functions(function, *class_hierarchy);
 
   auto function_is_stub = [&symbol_table, &model](const irep_idt &id) {
     return symbol_table.lookup_ref(id).value.is_nil() &&