Relax an assertion when creating document loaders
Created attachment 231670 [details]
Committed r169026: <http://trac.webkit.org/changeset/169026>
This appears to have broken http/tests/navigation/forward-to-fragment-fires-onload.html on the debug WK2 bots.
For a crash log, see: http://build.webkit.org/results/Apple%20Mavericks%20Debug%20WK2%20(Tests)/r169277%20(4854)/results.html
For a history of when the test started to fail, see: http://webkit-test-results.appspot.com/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=http%2Ftests%2Fnavigation%2Fforward-to-fragment-fires-onload.html