We need to general pytorch cache defragmentation on an appropriate level for
aimdo. Do in here on the per node basis, which has a reasonable chance of
purging stale shapes out of the pytorch caching allocator and saving VRAM
without costing too much garbage collector thrash.
This looks like a lot of GC but because aimdo never fails from pytorch and
saves the pytorch allocator from ever need to defrag out of demand, but it
needs a oil change every now and then so we gotta do it. Doing it here also
means the pytorch temps are cleared from task manager VRAM usage so user
anxiety can go down a little when they see their vram drop back at the end
of workflows inline with inference usage (rather than assuming full VRAM
leaks).
