Fix bad URI errors.

Previous code override the `path` variable, but we should refer
to the `location.path` instead.

actionpack/lib/action_dispatch/testing/integration.rb

@@ -290,7 +290,7 @@ def process(method, path, params: nil, headers: nil, env: nil, xhr: false, as: n
             url_host += ":#{location.port}" if default != location.port
             host! url_host
           end
-          path = location.query ? "#{path}?#{location.query}" : path
+          path = location.query ? "#{location.path}?#{location.query}" : location.path
         end
 
         hostname, port = host.split(':')