Edje UI mirroring: Fix UI mirroring for GROUP parts.

GROUP parts were not mirrored with the rest of the edje object,
this commits fixes that.

This is an improvement of the now reverted
55b62bbd70.

Thanks to cedric for the pointer that lead to this commit.

Ref T3021

src/lib/edje/edje_calc.c

@@ -818,6 +818,9 @@ _edje_part_description_apply(Edje *ed, Edje_Real_Part *ep, const char *d1, doubl
                   ted->recalc_call = ted->dirty = ted->recalc_hints = EINA_TRUE;
                   _edje_recalc(ted);
                }
+
+             edje_object_mirrored_set(ep->typedata.swallow->swallowed_object,
+                   edje_object_mirrored_get(ed->obj));
           }
      }