un-extract the Arel visitor for SelectOptions
un-extract the Arel visitor for SelectOptions

This does not need to be a separate method since a2040ee which removed
the Oracle12 visitor, and essentially reverses the Oracle prefactor
from 8d04c28.

joonyou/rails,kddeisz/rails,Stellenticket/rails,yawboakye/rails,MSP-Greg/rails,MSP-Greg/rails,esparta/rails,EmmaB/rails-1,georgeclaghorn/rails,EmmaB/rails-1,kddeisz/rails,georgeclaghorn/rails,kmcphillips/rails,rails/rails,georgeclaghorn/rails,Stellenticket/rails,BlakeWilliams/rails,Erol/rails,EmmaB/rails-1,joonyou/rails,kmcphillips/rails,Envek/rails,yahonda/rails,lcreid/rails,Edouard-chin/rails,Envek/rails,Vasfed/rails,BlakeWilliams/rails,MSP-Greg/rails,Erol/rails,kmcphillips/rails,bogdanvlviv/rails,esparta/rails,Erol/rails,Envek/rails,kddeisz/rails,esparta/rails,yawboakye/rails,yawboakye/rails,esparta/rails,lcreid/rails,yahonda/rails,Vasfed/rails,rails/rails,Vasfed/rails,Stellenticket/rails,BlakeWilliams/rails,bogdanvlviv/rails,bogdanvlviv/rails,Vasfed/rails,kddeisz/rails,Edouard-chin/rails,bogdanvlviv/rails,Erol/rails,rails/rails,Edouard-chin/rails,Envek/rails,rails/rails,joonyou/rails,Edouard-chin/rails,MSP-Greg/rails,lcreid/rails,yawboakye/rails,georgeclaghorn/rails,yahonda/rails,BlakeWilliams/rails,Stellenticket/rails,lcreid/rails,kmcphillips/rails,yahonda/rails,joonyou/rails