Blender Git Loki

Fix T75542: toggling modifier visibility not working correct with undo speedup

The problem was that in direct_link_id_restore_recalc, recalc_undo_accumulated
should contain the changes from the target state to the current state. However
it had already been cleared at that point, to start accumulating changes up to
the next undo push.

Delaying the clear of this flag seems like the obvious solution, but it's hard
to find the right place for that (if there is one). Instead this splits up the
flag into two separate variables.

Reviewed By: mont29

Differential Revision: https://developer.blender.org/D7402