cleanup: unused and undefined methods

sql/field.h

@@ -4060,9 +4060,6 @@ class Field_string final :public Field_longstr {
   bool compatible_field_size(uint field_metadata, const Relay_log_info *rli,
                              uint16 mflags, int *order_var) const override;
   uint row_pack_length() const override { return field_length; }
-  int pack_cmp(const uchar *a,const uchar *b,uint key_length,
-               bool insert_or_update);
-  int pack_cmp(const uchar *b,uint key_length,bool insert_or_update);
   uint packed_col_length(const uchar *to, uint length) override;
   uint max_packed_col_length(uint max_length) override;
   uint size_of() const override { return sizeof *this; }