Further GtkListItemManager items-changed handling fixes
My previous MR has fixed only the first of 3 possible cases:
- ][
- )[
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As such, testsuite/gtk/listitemmanager still crashes from time to time.
This MR enhances the test and generalizes the fix to cover all 3 cases.
With these patches applied, I have run testsuite/gtk/listitemmanager about hundreds of times with these patches, without any failure.
Edited by António Fernandes