Make Trainer.__test_using_best_weights use cloud_io's load to support more storage backends (#3694)
Make Trainer.__test_using_best_weights use cloud_io's load to support more storage backends (#3694)

* Split out changes from #3563 to make that PR easier to review. This formats the file according to the Black formatter

* Store a reference to the trainer on the datamodule

Fixes #3682

* Update data_connector.py

* Update data_connector.py

* Update test_datamodules.py

* Support more storage backends in trainer.test using best weights

Similar to #3692

* Update trainer.py

* Update trainer.py

use cloud_io load directly
williamFalcon/pytorch-lightning,williamFalcon/pytorch-lightning