execution: remove per node gc.collect()

This isn't worth it and the likelyhood of inference leaving a complex
data-structure with cyclic reference behind is now. Remove it.

We would replace it with a condition on nodes that actually touch the
GPU which might be win.

execution.py

@@ -530,7 +530,6 @@ async def execute(server, dynprompt, caches, current_item, extra_data, executed,
                 #FIXME: this is probably a little zealous
                 # Torch code comments says some stuff about not actually freeing tensors on mempool
                 #context release. Explicitly garbage collect now.
-                gc.collect()
                 torch.cuda.empty_cache()
 
             if has_pending_tasks: