Revert "Allocate array of size NAME_MAXLEN"

This reverts commit 21d665a.

Author: SnoopJ

Objects/unicodeobject.c

@@ -6014,7 +6014,7 @@ _PyUnicode_DecodeUnicodeEscapeInternal(const char *s,
 
                     /* map to uppercase before calling getcode, which does
                      * case-sensitive comparisons */
-                    char buffer[256]; /* NAME_MAXLEN */
+                    char buffer[namelen];
                     size_t i;
                     for (i = 0; i < namelen; i++) {
                         buffer[i] = Py_TOUPPER(start[i]);