This reverts commit 948211679f.
This commit introduced some regressions in the test suite.
As this change is a core part of blender Bastien and I decided to revert
it as the solution isn't clear and needs more investigation.
The following tests FAILED:
62 - blendfile_liblink (SEGFAULT)
63 - blendfile_library_overrides (SEGFAULT)
It fails in (id_us_ensure_real)