With this the simulation cache pointer is copied over to the evaluated modifier.
This allows the original modifier to be removed without breaking the evaluated
modifier, which results in better decoupling. This can avoid issues when a
non-active depsgraph is evaluated in the background while the user is manipulating
the scene.
Also, it is now assumed that the simulation cache is always allocated even if
there is no simulation (similar to run-time data). This simplifies the code.
Pull Request: https://projects.blender.org/blender/blender/pulls/108976
87643d173e