unicodeobject.c doesn't make output strings ready in debug mode

Try to only create non ready strings in debug mode to ensure that all functions
(not only in unicodeobject.c, everywhere) make input strings ready.
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 4e05490..56bd7b7 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -46,6 +46,10 @@
 #include <windows.h>
 #endif
 
+#ifdef Py_DEBUG
+#  define DONT_MAKE_RESULT_READY
+#endif
+
 /* Limit for the Unicode object free list */
 
 #define PyUnicode_MAXFREELIST       1024