The test for bug 419132 tries to reload the window in an infinite loop, with a 60 second timeout. This is crazy, and the test has been disabled because of this (rightly so).
I have a patch which makes the test load 4 times, and then finishes. Technically, two times should be enough (since the original test case needs to trigger the gc, which will happen some time in the future tests), but I decided to cut it some slack!
Created attachment 526512 [details] [diff] [review]
Comment on attachment 526512 [details] [diff] [review]
Could you also trigger a GC after every other load? There's code in the patch in bug 588990 which adds API to SpecialPowers to trigger a GC. Feel free to steal the implementation from there you also review it (not the whole patch, just the gc implementation).
r=me with that.