If an item name (and ID) is provided, never successfully match only
based on the item index.
This can lead to matching to a complete different ID than the intended
one, which can be catastrophic for the integrity of the next resync.
Also, do not require sucessful match on both source and destination
data, this will always fail in case e.g. an item is removed from a
collection, and can prevent detecting required resync from that
collection then.
This commit also enables new 'harder' test in unittests, added in
previous commit, which is now expected to pass.
Pull Request: https://projects.blender.org/blender/blender/pulls/144429
cbf763e700