py: Simplify some cases of accessing the map of module and type dict.

mp_obj_module_get_globals() returns a mp_obj_dict_t*, and type->locals_dict
is a mp_obj_dict_t*, so access the map entry of the dict directly instead
of needing to cast this mp_obj_dict_t* up to an object and then calling the
mp_obj_dict_get_map() helper function.

py/builtinhelp.c

@@ -145,13 +145,13 @@ STATIC void mp_help_print_obj(const mp_obj_t obj) {
 
     mp_map_t *map = NULL;
     if (type == &mp_type_module) {
-        map = mp_obj_dict_get_map(mp_obj_module_get_globals(obj));
+        map = &mp_obj_module_get_globals(obj)->map;
     } else {
         if (type == &mp_type_type) {
             type = MP_OBJ_TO_PTR(obj);
         }
-        if (type->locals_dict != MP_OBJ_NULL && MP_OBJ_IS_TYPE(type->locals_dict, &mp_type_dict)) {
-            map = mp_obj_dict_get_map(type->locals_dict);
+        if (type->locals_dict != NULL) {
+            map = &type->locals_dict->map;
         }
     }
     if (map != NULL) {

py/runtime.c

@@ -1394,7 +1394,7 @@ void mp_import_all(mp_obj_t module) {
     DEBUG_printf("import all %p\n", module);
 
     // TODO: Support __all__
-    mp_map_t *map = mp_obj_dict_get_map(MP_OBJ_FROM_PTR(mp_obj_module_get_globals(module)));
+    mp_map_t *map = &mp_obj_module_get_globals(module)->map;
     for (size_t i = 0; i < map->alloc; i++) {
         if (MP_MAP_SLOT_IS_FILLED(map, i)) {
             qstr name = MP_OBJ_QSTR_VALUE(map->table[i].key);