New test to show that params is NOT actually a HashWithIndifferentAccess

#1405 was not correctly fixed... params in a controller is not a HashWithIndifferentAccess, only env['router.params'] is.

From within a controller scope:
1.9.3-p484 :012 > self.env['router.params'].class
 => ActiveSupport::HashWithIndifferentAccess
1.9.3-p484 :013 > params.class
 => Hash