This test checks the following case:
* Create an iframe
* Set its location to about:blank
* In a setTimeout(), navigate to a non-blank page
The iframe navigations should not create new history entries, even though the non-blank navigation is after the load (there is only one history entry in the iframe context, and it is about:blank). 

============== Back Forward List ==============
curr->  http://127.0.0.1:8000/navigation/location-change-repeated-from-blank.html
            http://127.0.0.1:8000/navigation/resources/pass-and-notify-done.html (in frame "i")
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