Deal with circular relationship between world and config
Created by: myronmarston
RSpec::World#initialize
references RSpec.configuration
and RSpec::Configuration
references RSpec.world
in a few
places. This circular dependency is not ideal and has triggered
infinite recursion during some recent changes I've tried to make.
It would be nice to get rid of it entirely, but for now, this is
the simplest change I can make it solve my immediate problems.