a4aee6a997
Some `ImagePartialUpdateTest` test are calling code that needs access to a valid `G_MAIN`. So store the generated main there as part of the setup step, and reset G_MAIN to its original value (should be NULL) in the teardown step. NOTE: Things like `ID_BLEND_PATH_FROM_GLOBAL` and `BKE_main_blendfile_path_from_global` are pure evil. It may be necessary in a very few small cases, but their current usages need a lot of strong cleanup. Pull Request: https://projects.blender.org/blender/blender/pulls/108189