While applying liboverrides on linked data, RNA code (in
`rna_property_override_check_resync`) would detect a lot of false positive
regarding IDs needing resync, because the temporary ID used to apply
overrides was always local, breaking the libraries comparison check.
NOTE: that whole 'apply liboverrides' code could use some refreshment,
it did not change much from initila version several years ago, we now
have better tools and control over non-main data.
But for now the 'trick' in that commit should do the job, ultimately
those temps IDs should never be put in Main at all.
d5a88f9bf4