Apply suggestions from code review

Co-authored-by: Andrei Maiboroda <andrei@ethereum.org>

Author: chfast

test/spectests/spectests.cpp

@@ -480,6 +480,7 @@ class test_runner
             args.push_back(*arg_value);
         }
 
+        assert(args.size() == instance->module.get_function_type(*func_idx).inputs.size());
         return fizzy::execute(*instance, *func_idx, args.data());
     }