On GCC in release mode (and maybe also debug mode without ASAN enabled),
allocating an `AssetLibraryService` will reuse the space that should
have just been freed. This made a test fail, as it was testing that new
memory was allocated and not some old instance reused.
To ensure that the calls that should allocate a new block of memory
return a unique pointer, I added some dummy allocation to the test.
No functional changes to Blender
3edae09eaa