Memory leak when using ListView, Canvas, and some Frames

I've attached the required (pretty minimal) example to reproduce the bug.

How to use:

$ unzip bug_mem_leak.zip
$ cd bug_mem_leak
$ export QML2_IMPORT_PATH=$(pwd)
$ qmlscene main.qml

Make sure you're ready to `Ctrl-C` out of it as it fills up the memory real quick. 4GB RAM + 4GB swap in like 5 seconds!

I've added multiple "helper" TODOs for what changes to make in order to get the bug to appear or disappear, just `grep -r 'TODO' .` for instructions.--