BIG Reorganize examples (#4213)

* Created using Colaboratory

* [examples] reorganize files

* remove run_tpu_glue.py as superseded by TPU support in Trainer

* Bugfix: int, not tuple

* move files around

src/transformers/trainer.py

@@ -333,7 +333,7 @@ class Trainer:
             total_train_batch_size = (
                 self.args.train_batch_size
                 * self.args.gradient_accumulation_steps
-                * (torch.distributed.get_world_size() if self.args.local_rank != -1 else 1),
+                * (torch.distributed.get_world_size() if self.args.local_rank != -1 else 1)
             )
         logger.info("***** Running training *****")
         logger.info("  Num examples = %d", num_examples)