Remove failing test which was wrongly introduced.

This test was introduced in pull request #2577. The author of the pull
request included the test, which was originally in #2230, at the same
time as fixing a separate (but related) bug. However, the author did not
include a fix for this test, so when #2577 was merged, a failing test
was introduced.

So I am removing the failing test for now. If anyone wants to fix the
bug, please do so and submit a complete pull request with a test and
a fix.

railties/test/railties/mounted_engine_test.rb

@@ -235,10 +235,5 @@ module ApplicationTests
       get "/weblog_engine_route_in_view"
       assert_equal "/weblog", last_response.body
     end
-
-    test "request url for controller action when engine is mounted at root" do
-      get "/weblog"
-      assert_equal "http://example.org/weblog", last_response.body
-    end
   end
 end