We store various lazily calculated caches on meshes, some of which
depend on the vertex positions staying the same. The current API to
invalidate these caches is a bit confusing. With an explicit set of
functions modeled after the functions in `BKE_node_tree_update.h`,
it becomes clear which function to call. This may become more
important if more lazy caches are added in the future.
Differential Revision: https://developer.blender.org/D14760
Continuing the refactors described in T93602, this commit moves
the face dot tag set by the subdivision surface modifier out of
`MVert` to `MeshRuntime`. This clarifies its status as runtime data
and allows further refactoring of mesh positions in the future.
Before, `BKE_modifiers_uses_subsurf_facedots` was used to check
whether subsurf face dots should be drawn, but now we can just check
if the tags exist on the mesh. Modifiers that create new new geometry
or modify topology will already remove the array by clearing mesh
runtime data.
Differential Revision: https://developer.blender.org/D14680
