Until now, many online textures were retrieved via the default texture store, which causes them to never be removed from GPU memory. It also has a performance overhead due to mipmap generation (which will be avoided via ppy/osu-framework#1885.
It is dangerous to use this as it doesn't correctly handle contexts and can cause issues that will never actually arise in normal execution.
# Conflicts:
# osu.Game/Database/SingletonContextFactory.cs