Improvements for `test_filesystem.py` (#1394)
Improvements for `test_filesystem.py` (#1394)

* add a random prefix into `path_to` to avoid name clash as we will eventually run tests on the same filesystem with different configs

* add `remove` and `rename` tests

* add intial tests for `gs`
tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io,tensorflow/io