Bug 831933: Force focus the active window so the focus manager knows what is going on.

I managed to reproduce this a few times in my VM. What happens is the focus manager doesn't know what is focused. I've seen this before on linux, focus there is not right in the platform.

I made a couple of changes, waiting for the first page to load properly and focusing the last open window to tell the focus manager that it is actually focused. That seemed to solve the problem for me.

I also removed that large comment about bug 614079 since it seems to refer to a part of the test that is no longer present.