<rdar://problem/8636239> and https://bugs.webkit.org/show_bug.cgi?id=53785 - Extraneous back/forward entries with dynamically appended iframes.
This page appends an iframe after onload. That iframe should *not* result in a new back/forward entry in the session history.


============== Back Forward List ==============
curr->  (file test):fast/loader/dynamic-iframe-extra-back-forward-item.html  **nav target**
            (file test):fast/loader/resources/notify-done.html (in frame "<!--frame1-->")
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