Merge pull request #17473 from vipulnsward/rm-unused-method

Remove unused duplicated method `add_column_position` from AbstractMysqlAdapter.

activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb

@@ -585,14 +585,6 @@ def type_to_sql(type, limit = nil, precision = nil, scale = nil)
         end
       end
 
-      def add_column_position!(sql, options)
-        if options[:first]
-          sql << " FIRST"
-        elsif options[:after]
-          sql << " AFTER #{quote_column_name(options[:after])}"
-        end
-      end
-
       # SHOW VARIABLES LIKE 'name'
       def show_variable(name)
         variables = select_all("SHOW VARIABLES LIKE '#{name}'", 'SCHEMA')