Merge pull request #12819 from vipulnsward/also_dup_column_types

Also dup `column_types` in AR::Result `initialize_copy`

activerecord/lib/active_record/result.rb

@@ -85,6 +85,7 @@ def last
     def initialize_copy(other)
       @columns      = columns.dup
       @rows         = rows.dup
+      @column_types = column_types.dup
       @hash_rows    = nil
     end