Accelerator end training (#18910)

* add accelerator.end_training()

Some trackers need this to end their runs.

* fixup and quality

* add space

* add space again ?!?

examples/pytorch/multiple-choice/run_swag_no_trainer.py

@@ -637,6 +637,9 @@ def main():
                 output_dir = os.path.join(args.output_dir, output_dir)
             accelerator.save_state(output_dir)
 
+    if args.with_tracking:
+        accelerator.end_training()
+
     if args.output_dir is not None:
         accelerator.wait_for_everyone()
         unwrapped_model = accelerator.unwrap_model(model)