Merge pull request #12091 from rywall/pluck-optimization

[Perf] Don't use Enumerable#next in pluck since it is very slow

activerecord/lib/active_record/relation/calculations.rb

@@ -161,8 +161,7 @@ def pluck(*column_names)
         result = result.map do |attributes|
           values = klass.initialize_attributes(attributes).values
 
-          iter = columns.each
-          values.map { |value| iter.next.type_cast value }
+          columns.zip(values).map { |column, value| column.type_cast value }
         end
         columns.one? ? result.map!(&:first) : result
       end