Patch ActionDispatch::Request::LOCALHOST to match any IPv4 127.0.0.0/8 loopback address

The entire 127.0.0.0/8 range is assigned to the loopback address, not only 127.0.0.0/24. This patch allows ActionDispatch::Request::LOCALHOST to match any IPv4 127.0.0.0/8 loopback address.