Remove an unused error code

sql/share/errmsg-utf8.txt

@@ -7796,8 +7796,6 @@ ER_WRONG_NUMBER_OF_VALUES_IN_TVC
         eng "The used table value constructor has a different number of values"
 ER_FIELD_REFERENCE_IN_TVC
 	eng "Field reference '%-.192s' can't be used in table value constructor"
-ER_NOT_SINGLE_ELEMENT_ORDER_LIST
-        eng "Incorrect number of elements in the order list for '%s'"
 ER_WRONG_TYPE_FOR_PERCENTILE_FUNC
         eng "Numeric datatype is required for %s function"
 ER_ARGUMENT_NOT_CONSTANT